Today I didn't get to play as much Halo 3 Beta today but here are my first impressions:
Matchmaking: Kind of slow and some times hangs in the lobby screen, at least in my experience. The interface is a bit more complicated than in Halo 2's interface but I think it works well.
Rumble Pit: Maps are kind of big for the 8 player matches, which means there are times when you'll be running around for a while for a target. Since there are only three maps I won't complain too much but a smaller map would make for more interesting rumble pits.
Team Slayer: Awesome, feels smooth and faster than Halo 2. This is where I think the beta really shines. The only problem you have during these matches that there are some balance issues with the weapons, you'll have to experience it to understand.
Well those are my first positive impressions I'm going back to play some more beta-ie goodness
