I haven't tried any of them, but they could be fantastic for prototyping, first throw-away versions, and projects that don't really matter.
For real r2.0+ production versions on projects/products that matter, I'd be suspicious that there are huge layers of libraries that get included, lots of code to run slow and provide bug habitat. But, it could also be that the developers have some optimization passes that strip out unnecessary code. It's something to check out carefully before committing. Of course, using one for a first throw-away version and examining it in detail can provide much info.
For real r2.0+ production versions on projects/products that matter, I'd be suspicious that there are huge layers of libraries that get included, lots of code to run slow and provide bug habitat. But, it could also be that the developers have some optimization passes that strip out unnecessary code. It's something to check out carefully before committing. Of course, using one for a first throw-away version and examining it in detail can provide much info.