i find i can use much more strategy and tactics in MP when i join servers with 16 or less players. My favorite is around 8 players.
When i joined a DM with 30 or so players, it was like Quake3 but not as good. Just run around and point and shoot, if you start getting fancy someone will come from behind and kill you.
Yeah, I find the smaller games more fun too. The 32 player games are too chaotic, especially the ffa ones. Because you just keep respawning and dieing over and over.