About two months ago, I started working with Axure Pro RP (www.axure.com). (Just for the record, I have no financial interest in the company.) The software allows non-programmers to create medium-fidelity prototypes. I've written and spoken extensively on how important I consider prototyping to be, so I thought some folks would like to hear my impressions of working with the program after two months.
* Very easy and fast to create prototypes
* Very little time needed to get up to speed with the program
* Allows for fair amount of conditional logic -- especially considering that the software is meant for non-programmers
* Comes with a good selection of widgets
* "Dynamic panels" allow for good Ajax-like state changes of portions of the page
* Doesn't allow for user feedback via something like DevNotes (see Jeff Peters' site for my DevNotes program)
* Very limited ability to add customized widgets -- and that by a hack
* No fancy DHTML capabilities
* No real programmability to extend the code
* How-to materials and tutorials are not extensive
Those are the bullet points. All in all, I'd say I'm quite happy with Axure. It's not nearly the behemoth that iRise is (another prototyping tool) and that's both to its advantage and disadvantage. Since my ultimate goal is to offload the majority of prototype work to others, the ease of use and short learning cycle is very important. Yes, I'd love it to be more capable, but, of course, that would increase the complexity.
As for the company itself, I've found the company to be responsive to my questions and requests. There is pending litigation from iRise for patent violation. I'm not a lawyer (thank you, God) so I won't offer my opinions of over-reaching lawsuits. Really, I won't.
My recommendation: Take a serious look at Axure if you're sold on the virtue of prototypes. Consider how quickly you can turn prototypes around using software like this. In my case, I typically have a new rev of the prototype within 48 hours of getting customer feedback. I think you may find Axure will change the way you build software for the better.
Axure costs $589 and the one-year subscription for updates and support costs $149.