XBL uses servers which go through other computers to connect the players. Sometimes you get an ok connection, sometimes you don't. If you acclimate, you're ok with it. It's kind of like being ok with black and white TV because you didn't know that HDTV exists. The less you know, the happier you are...
p2p Kaillera connects the 2 computers directly. There is no other communication. This gives you the best possible connection available(which sometimes may still not be great, but most times is better than going through a server). It's kind of like being ok with a flat screen CRT television because you couldn't afford an HDTV. Close, but no cigar.
However, the online vs. offline and XBL vs. p2p Mame discussion part of this is now over.
You can vote whatever way you want, but I urge only the people who plan on playing to vote...
QuiGon, you playing?