Bar the connection issues (which, once you get into a party you can stay connected to them as long as you want with no connection issues) I had a really good time.
Like Centrale said, the new button layout takes awhile to get used to, but I think it works more for the best. The graphics are excellent, the art is top notch the sound design is seriously some of the best I ever saw for multiplayer in any game ever and everything else is just so close to perfect that I am really surprised that this is just a small fraction of an unfinished game.
The new armor abilities really add a lot more to the game than I thought they would. Outside of the jetpacks - which I think are underpowered, all of them are very well balanced and great fun to use. The Elites should have more choices for them instead of just dodging though. I am thinking climbing would be cool.
My biggest issue with the beta is really that I cannot always pick the kind of mode *I* want to try out. For every round you get four choices of what can come next, and the options are usually game modes and levels you would expect from the last round, and the one before that, and the one before that. I can understand why they did this, but I am just really anxious to try out modes like Invasion and Spartans vs Elites, but cannot be playing the game for hours at a time.
That said, the new modes are seriously fantastic. Even the 'Meh' sounding ones like Stockpile kept me drooling for more!