When it comes to Halo, I would choose xbc(sometimes). But when it comes to any other game, I pick Kai. I just started playing Jedi Academy last night on Kai and it rocked. Me and my bro are trying to get more people to come and play Jedi Academy with us. Anyway, I would prefer Kai overall because xbc is full of idiotic noobs who kick me because I'm better than them. And the Kai community seems more friendlier than the xbc community. If you ask me, xbc has gotten cooler through out the last few months, but more people are starting to think that they're the best at Halo until they get beaten by me and my buddies. The only nice people that i've met on xbc are elites. But every time I join an elite room, there is almost always one newb who thinks that he is an elite. I don't blame them for trying to improve their skills, but swearing at us and calling us cheaters isn't gonna win our respect. So if I'm feeling good, then I would go to Kai but if I feel like hurting a bunch of disrespectful noobs, then I'll go to xbc.
I'm not putting down xbc. What I'm trying to say is that a lot of people who play on xbc are vicious and angry almost all the time. I'm not saying that this goes for everyone who plays xbc. It's only a fraction of the people on xbc that ruin the fun for the rest of us.