Note: I’m always little skeptical about these tool vendors who claim to provide solutions to everything…..to me, a good prototyper should be able to use just about anything – long as they could do it fast and get their point across effectively to their audience. I still think paper/pen is still pretty good

Adobe Flash/Flex: You can create data sets in XML, and generate real elaborate interactions.

(upcoming)
Microsoft Expression: Interactive Designer: Just like Flash but for WPF/E.

These simulators for the most part–the ones mentioned above–differ from the tools I mention here in that they are also document management systems or have some connectivity to a document.

I’ve been using Axure for a relatively long while now and I can tell you that there is pretty much no interaction I can’t prototype in that tool outside of drag and drop. There is a lot of facility for making the pages highly interactive without page loads, and this has allowed me to get a good idea of how usable an interaction is before it’s been fully designed.

Scott, there are a few inaccuracies in your discussion of Axure’s features. First, it does include a facility for creating page flows (scenario design). Admittedly, it’s rudimentary, but it’s been good enough for my purposes. Second, it does allow for limited data interaction. Axure has one page variable that it can play with, and you can make user interactions set the value of this variable. You can then set interactive elements on the page to react to this variable.

Regarding Axure as a Visio replacement, it *has* replaced Visio for me, nearly. The only thing I continue to use Visio for is site maps. And that’s fine with me. : )

One more thing… I think it’s important to note the cost of iRise… while it is a really excellent tool, it costs around $150,000. I’m not kidding and that’s not a typo. My company was looking into that vs. Axure and we contacted a rep who gave us this figure. We are no longer looking at iRise. : )

The best thing about Axure:
very easy to learn and use, I was productive since day 1
the worst thing:
it produces really big HTML files, so try to keep them short

While iRise in many ways is very powerful, I ultimately found that it’s key value was in being able to rapidly communicate a new concept. In other words, it worked when part of the early stages of an IKIWISI (I Know It When I See It) requirements gathering model, in which a design was sort of grokked from a set of high-level business requirements, and then I just cranked out a functioning simulation in a day or two, to which stakeholders then responded. *However*, when the proof of concept phase was completed, and time came to actually get into detailed design, it turned out to be far more effective to just whiteboard stuff and return to doing wireframes (either visio or xhtml or flash or some other combination of tools) in collaboration with designers and developers. Why? Well, there are many reasons…

One huge reason was that we found prototyping the functionality in the actual target environment to ultimately be a far beneficial approach. In doing so, we were not only validating the user experience, but also validating the technology.

This is maybe an even bigger reason: at least from my experience, these simulators by and large are not capable of rapidly prototyping ajax functionality or other highly customized interaction design in which things refresh at the element level or animate or whatever, which for me, is an essential component of modern interaction design – for that reason, they may become a constraining factor, since one might only consider design options that the simulator supports.

As Anders Ramsay points out, tools like iRise have a hard time in prototyping AJAX functionality. Here Ruby on Rails is the star. Because of the built-in possibilities to easy add autocomplete widgets, drag-n-drop interface and more.

I wrote about how we use it at work on my blog justaddwater.dk:

Justaddwater.dk: Ruby on Rails as a Rapid Prototyping Tool

But then AJAX throws a big stick in the works and currently I’m leaning toward Microsoft’s Expression Interactive Designer which from what I’ve seen to date is the most interesting RIA development tool out there. In fact even the Expression Graphic Designer tool is an eye opener – effectively replacing both Illustrator and Photoshop in the one tool (with decent web integration) and currently for free!

Adobe the guys who you would have expected to lead in the simulation space (but have yet to step in) are likely to miss the boat – again

As a former user of Axure and current user of iRise, I think the price point discussions are appropriate and highly necessary. As a solo practitioner in-house, where most everything I did was viewed as 100% overhead, Axure did what I needed it to do and it did it well. The price point at purchase was around $500. We also were not doing a lot of work with RIA’s.

Now that I’m back in the consulting world, I’m fortunate to have access to iRise. It’s much more robust than Axure. My view is that it is the enterprise level equivalent and Axure is more of the smaller shop version.

There are things I could do in Axure that I cannot do in iRise and vice versa. I would imagine that convergence of these tools or the features of these tools will be something to watch in the future.