Virgo 3.0 is compatible with Virgo 2.1 from a tooling perspective, so the latest tooling is compatible with 3.0 if you choose 2.1. Clear as mud?
As for stability, Miles is motoring through the bug backlog so I would think there is a small risk of perturbation, depending on the quality of the regression test suite in Virgo IDE (which I can't speak for).
Note that we're in the middle of a major refactoring; resolving a lot of dependency issues and so on, so we haven't been able to be as responsive to immediate issues as we'd like and the nightlies are going to be a bit of a crap shoot as we pull old dependencies out. But that should be settling down.
Just made a bunch of changes that should really simplify the whole problem of support for different versions. Hopefully you won't even need to worry about this issue anymore. Just select Virgo Runtime as server, specify your install directory and you're good. This is on a branch right now, but as soon as we get it into master, feedback would be great. See bug below: