It's a friendly community, with a wide age distribution (lots of old quakers like myself). If you don't like death match, clan arena or CTF, login to a CTS defrag game (time races for movement training).
I gave Xonotic a go a few minutes ago. The game is nice but right now I can see 6 only servers populated. That's not a lot to be honest.
Sometimes it's hard to find a deathmatch game, so you end up joining clan arena, getting killed and then spending the remainder of each match spectating and not actually improving your skill. Freeze tag is huge fun but it's rarely voted for.
The one good thing about the small player base is that you will always bump into those superhuman players who destroy everyone. That gives you something to aspire to. Once you start leveling up to them, you know you're getting good.
I've always been amazed in particular by how polished it is for an open source game. Don't think I've ever heard anyone that tried it say they didn't enjoy it either, though generally folks don't stick around, save for a couple.
Most of the current playerbase is situated in Europe though I think, so you gotta play at times that make sense for those time-zones if you wanna see players (evenings usually pretty active).
I've probably killed you / been killed by you a bunch of times.
You're right about the Russian presence, it has gotten to the point where using "))" to indicate smileys has become a community thing, Russian or not :D