I'm about to start up a project, building a Flex application that will live on an intranet.
The project is to be finished in three months.
The features of Flash Builder are very inticing and would really help us, especially the designer-developer worksflow.
I have played with the Flash Builder beta and it seem pretty stable, but is it stable enough?
Do I dare use it or am I in for a lot of pain if I do?
Has anyone used it for "real" projects?
Standard speil is "don't use beta products in a production environment"
reality is that if you want to be at the front of the game and trust the supply of that product its a risk management decision.
I faced a similiar situation with flex 3 beta, if I hadn't gone forward with flex 3 we would not have beaten out our competitors.
Beta 1 is to unstable but beta 2 should be available soon and that would be much closer to the current flex SDK which seems reasonably stable. So the development environment (flashbuilder) is not production ready but I think the sdk is close enough. Its a risk for sure but I don't think its any bigger than the risk of either being left behind. The main thing is to be more thorough with testing and be prepared to do some updates to your project as soon as flashbuilder goes gold.
 when flex 3 was released it broke our project in several places so 60 hours went into debugging and retesting the effected areas.