I find selectively pulling packages from unstable quite useful, and usable, at least on a server. Generally, it will want to upgrade a few core packages like libc/libstdc++, but I don't find that to be a problem. It doesn't actually cause a need to upgrade vast swaths of the OS, only the few core packages, and I trust that those likely still work. :)
It's possible that the interdependence of desktop packages might be greater and make it infeasible to usefully do for a non-server package without upgrading almost the entire OS, I haven't really tried that.