Keeping in mind this is a beta, I'm pretty happy over all; but not blown away.
I like the fact that they are bringing back things from BF2, like commander mode, squad VOIP and "limited" ammo for the main guns in vehicles.
I like that they are giving us destructible environments (busting through walls with a tank is always a hoot) and tweaking weapons to be slightly more realistic (RPG and tank rounds have a much steeper drop off).
I like that they are restructuring the classes, once again bringing back BF2 game play.
I like that you can interact with the maps more (I find all sorts of cool hiding places that in BF3 you would just get knocked off due to invisible walls) you find yourself using more things as cover because you are able to lean and peak around them.
I do not like viability going to crap on this map after the building goes down, though we all know that's actually what happens in the real world.
I don't like how the controls feel a little awkward (but same thing happened when Valve gave us CS:S, hoping DICE will tweak things as more time passes).
After a day of play, that's how I feel about the game. I think that DICE did a good job at the game and look forward to things getting more polished.
Side note: Has anyone else discovered if you use your tank to ram the crap out of another person's tank head on you will lifte their tank over yours? It's been useful for me, since most of the time the guy gets confused as heck and it gives me a chance to place a few more rounds on him; or, one of my team member can c4 him while he can't shoot.