We have branched in preparation for a 2.5 stable release. I would say across the board it is more stable, balanced and fun than the current stable release (2.4). However, a couple of late changes still need to be checked for balancing/problems. The two big ones are the change in soldier stat growth and the new reaction fire panel. Even if these do undergo further revision, I don't believe either would cause significant problems in their current state.
I'm currently unable to spend almost any time on finalising 2.5, so I can't say a release is imminent. But in terms of stability and performance, we're just about there.