Sometime ago in 2009, John Nack from Adobe ask for feedback on Photoshop as a tool for iphone developers.
Here is a collection of those peoples' opinion on Fireworks as their tool

I know this is a question about PS but I actually prefer FW for these reasons: Pages, States, Vectors. I guess you would need to add that to PS but then again why would you replicate those features?
There are widget sets for either (the default iPhone OS buttons and controls).
FW has an extension that lets you script mockups to then export as web apps.

I like the idea of master-pages (like fireworks). Right now I’m stuck to using the timeconsuming layersets (sorry don’t know the exact english word).

I don’t think Photoshop is the right tool for the job, so rather than waste time on adding features to Photoshop, why not put those resources into Fireworks, which is already a much better tool for UI design (with hyperlinks, pages, masterpages etc).
I’m surprised that Adobe doesn’t understand its own products and how they are best used.

Seriously…

http://jcorrea.es/2008/08/07/iphone-gui-as-rich-symbols-for-fireworks/
When is Adobe going to stop with the Fail and get with the Win?
Fireworks dude, Fireworks. They are probably in your building, maybe another floor. You should have a chat with them.
And when you get back, you should write a blog post about how a photo manipulation software package is not really the right product for mobile software UI design.
Look, we all understand iPhone is THE hot tech product of the year, and we all know by now that Adobe is 98% driven by marketing, but this is really unbelievable. Do you really think that this equation is going to work?
Adobe popular product +
Current technological hype =
more profit!

Mike nailed it beautifully, stop trying to make Photoshop do things its bad at. Thanks to this idiocy there is a whole generation of designers using a hammer to put screws in.
And what on earth is the point of trying to jump on the iPhone UI bandwagon? Why add features for something so very specific?
I want to bang my head against a wall every time I see a UI done in Photoshop, separate layers for each button and the text on the button, having to marquee select one side of the button cut it move it then stretch the middle to resize them. IDIOTIC!!!
Don’t say use vectors because thats just as stupid, if you make every element out of vectors then it becomes utter hell just trying to select something because the vector pointer can select any vector on the stage at will but there is no highlight to tell you its going to happen, making it impossible to draw a box around points once you have enough overlapping vectors. Don’t tell me to lock layers because the lock control is so TEDIOUS compared to FW and IL.
So instead of wasting time doing this why don’t you send some more people to work on Fireworks and make it less clunky so people would stop opening it and laughing without realising how good it can be.

The company I work for uses Fireworks for designing applications for iPhone, Android, Flex, Silverlight, JavaFX, etc. (not websites) over Photoshop. The number of timesavers, efficiency tactics that can be employed and vector + bitmap design capabilities in Fireworks makes it the perfect app for designing UIs. Lately, I’ve been feeling that Fireworks has been kicked to the curb, which is a shame.

Why use Photoshop for iPhone at all? I feel very strongly that Photoshop should be for photos, not for designing UI or web content. That’s what Fireworks is for, and it does an ABSOLUTELY AMAZING job at it. I use Fireworks every day developing software for the iPhone, and it fits into my workflow beautifully. I can save a PNG in Fireworks (the native image format for iPhone and Android development, btw) and see how changes are reflected in the iPhone simulator almost instantly. I can manipulate graphics, art, and text as objects and apply styles to make things look great.
Please, please, please – don’t try to get people using Photoshop instead.

[So A) it's not used to design graphics for mobile apps, and B) it's not supposed to be? Thanks for clearing that up for everyone. --J.]
You may have been sarcastic, but you actually nailed it!

What I’m wondering is: why did you take time to respond to that post, ignoring the people that are saying they prefer to use Fireworks for UI design? Ignoring the issue doesn’t make it go away.
[I'm happy that people like using FW for this kind of work. They're welcome to keep using it for that purpose. But a heck of a lot of people use PS for screen design (note that it was a PSD and not a PNG that those guys posted). --J.]

What you seem to complete fail to understand it that indeed what USERS do with Photoshop defines the product AND what they expect for new releases.
Sites like dearadobe.com and adobeuigripes.tumblr.com are here to stay it seems.
[Of course those sites will always exist, because no matter what we do, no matter how many improvements we make (small and large), there will always be more to do. And it's not like the Adobe Gripes guy is going to say, "Wow, Adobe has made some real improvements; let me start talking about that." It's far more entertaining (and draws far more eyeballs) to fire off streams of profane bitching. That's fine, and there *are* plenty of things that we collectively should make better. I'm just not holding my breath for any props when we actually do it. --J.]

Unless you guys start focusing on quality instead of quantity and take back control from the marketing department when it comes to product development.
Seriously, have a look at Fireworks. It does iPhone UI development TODAY.
[Good. I wasn't asking about Fireworks. And it doesn't matter how many nervous FW devotees come here and pump up the volume: lots of people like using PS for screen design, and it's perfectly legitimate to try to make them happier--in PS. --J.]

Given that so many people like working with Fireworks I can see a lot of value in sitting down with a heavy Fireworks user and see how they design a button, where Fireworks s making that process faster than Photoshop.

Fireworks is a brilliant product, the best I know for creating screen (i.e. UI) elements.
Photoshop is a brilliant product, the best I know for creating photo/print elements.
Let’s not push Photoshop any further beyond its capabilities. There’s a ton of infrastructure in Photoshop that’s never used for screen work, and there’s a ton of stuff in Fireworks never used for photo work.
Here’s an idea: really, really polish Fireworks, make it so it doesn’t crash regularly, make it load faster and cleaner, and make it use native OS widgets (instead of the abstracted, blah Adobe UI), and charge $100 more.
That’s right, charge more. Make Fireworks a more efficient, more stable, more native product and I’ll gladly pay twice what you currently charge. You don’t even have to update it’s feature set.

I’ve created the interfaces for two iPhone apps and am working on two more.
Though I used Photoshop to create the images for two of them (i.e. digital painting), it never occurred to me to use anything but Fireworks to create the interface elements.

In the same way, it would never occur to me to use Photoshop to create web site interface elements instead of Fireworks.
Fireworks is specifically an application for creating screen graphics as opposed to print graphics. Hello?
I’ve been using Adobe software since Photoshop 2.5, but lately I’m astonished (and appalled) at Adobe’s insistence on forcing square pegs into round holes.

In the same vein, I second the comments about refining the existing applications instead of piling on pointless “features” every time accounting wants a new version to sell.

Instead of duct-taping more “functionality” onto Photoshop, refine Fireworks into the “must-have” app for all iPhone developers.
It already is for me.

Quote : “Yes, Fireworks is cool when you design a small ‘This is my homepage’ site. When you create a page for the biggest regional insurance company, for regional MTV, for biggest regional news-site, for the biggest regional advertising agency, things get REALLY complicated REALLY fast, and then only the power of Photoshop can help. So, FW lovers, show me what you have done in Fireworks.”

Do you realise you tell us almost complete non***? Do you mean Fireworks is for designing small “homepages” and only Photoshop can design “big websites”?? Is it because Ps is BIG and Fireworks is small (when you compare their download size)? ;-)
Well, let me disappoint you! Fireworks has the power to create the perfect graphic assets for both the smallest and the biggest of websites!
It can be used successfully by creative individuals or by whole teams of designers.

Its power lies in the fact that it is mostly vector-oriented app, but it has also a few nice bitmap tools in its toolset. It has live effects. It is intuitive to use — especially to novice users. It has Symbols — when used wisely, then can help you speed up your workflow, and a lot — create one symbol (example: create a red aqua button with white text, use it 100 times in all of your pages/layers/states in one complex Fireworks file, and when needed, update one of the buttons once, and see all instances of this button update instantly in all places! power!). It has Pages/Layers/States, and this speeds up your workflow, too — for example, have the header and footer part be shared accross all Pages, but design separately only the main content area in them! Also, click on an object, edit instantly color, stroke, text, effects, gradients, etc., in one place, in the Property Inspector — no need to have 10 panels open just to change a few properties of any vector or bitmap object!
Should I continue? I don’t think so…
Professional designers that use Fireworks for their screen/Web/UI designs, can speak for themselves. And some of them already have spoken here, in these comments…

Finally, I will show you an illustration, made entirely in Adobe Fireworks:
http://optimiced.com/en/?p=739

This illustration is the contest winner in a recent Fireworks contest; the author is Lucian Dragomir, a talented Fireworks designer.
The illustration is made from A to Z in Fireworks, and everything that you see, is pure vectors!
Does the illustration look unprofessional to you?
Does it look like Fireworks is an application that can create only second-grade graphics (for Web/screen)?
Does it look like all of this creative power, so strongly demonstrated in onlyone image, is only enough to be used for creating lame “homepages”, but cannot be used to create first-class graphics for any website — MTV.com included?
Because, you know, it doesn’t look so to me…
And — question: Can you (re-)create the same kind of image in Photoshop, without using a single bitmap or a mask, only with vectors? Can you create it in such a way that if you have a repeating element in the design (for example, a little silver screw), you can edit it once and made it change in 150 places simultaneously? If yes, then you don’t really need Fireworks:)
If no, then don’t speak so lightly about this nice graphic app that you probably never used because you prefer Photoshop…

You cannot merge Fireworks with Photoshop!
First, Fireworks is dedicated for editing screen/Web/UI graphics. As such, it has much less features than Ps, but they work much better in the area that Fireworks excels.
Second, Fw and Ps have too different workflows and UI. In Fireworks, you don’t think layers, you think objects. In Ps, you think layers. In Fireworks, this workflow works best for screen graphics, prototypes, UI. Click on an object and edit it. In Ps, this doesn’t work so. Without layers in Ps, you can’t do anything. In Fw, you can work with your Layers panel closed.
Third, Fw is mostly vector-based. Is Ps vector-based? I don’t think so.
Fourth, if you merge Fw into Ps, what’ll happen is probably Ps will copy some of the features that Fw has into its already over-crowded features list/toolset, and that’s it. Ps will continue to work as it is now, but its workflow is not usable nor intuitive, for screen/Web work, at least. And to change the way that Ps works… no, this will never happen, Ps users are accustomed to this un-intuitive way that Ps works. But Fw users are accustomed to the easy way Fw works. So, no way, IMHO…