My DCS is currently at 4.0 and has been running flawlessly since day one. No issues with creating lashups (Don't let certain people know I said that phrase) no bugs have shown themselves, etc, etc.
I have not tried to change sound files yet but I'm sure that will be coming with PS3 upgrade kits in a year or so.
With that said should I install the latest and greatest? If yes, more than likely I'll do it at the April York show.