I spent 1 1/2 years working on a large CAB application for a local Bank and was left with a bitter taste by CAB...
Primarily because it was such a confusing framework to use. Developers found it really difficult to grasp WorkItems and we overused loosely coupled events almost using them to control our process flow.
ObjectBuilder... Say no more.
The guidance / reference implementations were, hmm, not great. They rendered their own views un-testable by having links to concrete classes which would instantiate views, generally breaking the whole idea of a testable design.
So it's been with a little bit of fear that I downloaded the Prism guidance to have a look at what the WPF Composite Guidance is like.
First impressions have been really pleasant. Yes I have seen ObjectBuilder2 (sounds like some dodgy horror movie title), but thankfully have been pretty shielded from it.
WorkItems are gone - this is awesome. They were really unpleasant to explain to people.
DI has taken over bigstyle. Register everything with the Container, and things get resolved automatically. I was a little bit worried that I'd be swimming through Xml soup but smartly the IoC configuration is done in code at a module level.
Things generally seem neater and cleaner. I got my 1st Application up and running in 30 minutes or so, compared to a few hours with CAB.
So generally I'm pretty pleased. Add to that there is a Silverlight version. Cool! I'm sure I'll become a regular contributor to the Prism forums!