I haven't played TCon very much, but based on the fact that the few times that I did play TCon, I had no trouble joining private matches, I'd have to say TCon was way better.
So far it's almost impossible to even get a private match going.
It's sad really, because they clearly put a lot of thought into the multiplayer game. There are several modes, lots of characters, lots of customization, a leaderboard, and the limited gameplay that I've managed to get in is pretty fun. It's just too bad that the thing can't seem to ever connect two people to the server at the same time.