After not enjoying this last night i've been playing today and i'm really liking it. I think it's better than Blops.
The maps are really good. Only one I don't like so far is Resistance.
Constant air support is a pain though. Doesn't help that nobody seems bothered about shooting things down either

Encountered my first IMS earlier. Heard a weird noise,didn't know what the chuff it was and then I was dead. The explosion has a huge range on it!
Booby trapped air drops are pointless as you can tell quickly that it isn't a care package

I've only really been playing Kill Confirmed. As it doesn't say how many people are online i've no idea how many are playing what modes. Kill Confirmed is great fun. Annoying as chuff when you're just about to collect a dog tag and you get killed!
I wouldn't say it's the most balanced COD yet. Any game that allows a team to have an attack chopper and AC-130 in the air at the same time isn't balanced IMO.