[Cel Skeggs]

We use IterativeRobot. This is mostly because we switched to Java last year (so we've used it for two years) and it worked well enough for us both years.
I see the Command-Based framework as writing a large amount of code for you, which makes it much harder to debug when a program doesn't work.
We also have a Java class being taught separately at our school, so we can require that all Software students are taking this class or have equivalent experience, so that we don't need to worry about teaching anyone how to program.
We haven't actually programmed our robot using the Command-Based framework yet, but if we're going to use a complex framework, we'd rather write the framework ourselves during the preseason (and release it, of course), so that we have someone on our team who knows how the framework works and how to extend it.