The 5.0 release bump was pretty awesome for a few months... there were many populated servers at all times. Since then it's settled into a few interconnected communities that enjoy different game types, but there are probably 100-200 regulars that play at least weekly, with a couple dozen on most every afternoon, night, and late night at any given time.
One note on my above post about Arsenal, which was 7 months ago... arsenal/team arsenal are still the dominate game types, but those of us who enjoy DM, TDM, and other game modes have started to see an uptick in other game type servers active more frequently, usually getting a nice 10-12 server going without much trouble most nights. Quite a few people deserve credit for that (Graslu, Shemp, and others) because they have been constantly promoting the game, streaming, recruiting new players, and spending hours getting servers going and populated.
There aren't thousands of people playing but it's a got a pretty tight little community with some new players trickling in often.