I really don't know where all these mw2 fans have come from, last time i checked the multiplayer in that was the worst balanced mp of any of the CoD titles.
I honest to god don't understand how people are saying that it's not better, unless these people are the ones that actually enjoy camping, boosting and quickscoping every game they play.
Black ops multiplayer has balanced uncountable atrocities that infinity ward never bothered to patch in mw2.
Weapons - Burst fire weapons are now A LOT less powerful and are on par with other assault rifles/smgs.
Snipers are now for sniping and not for running around like some try hard lunatic and quickscoping your way to a funny game winning kill.
Shotguns are now a primary weapon and are even less powerful than the mw2 secondary shotguns! And what's more is they still fit in perfectly.
Launchers/explosives in general are less powerful and if they still really annoy you there's the option of the flak jacket perk.
Killstreaks - The main improvement to killstreaks is that they now do not stack with each other. You must earn all your killstreaks via your gun/grenades/melee etc, not your other killstreaks, meaning a 7 killstreak reward does not soon turn into a 25 kill streak reward. This promotes run and gunning a lot more and stops people cowering in a corner letting their streaks do the work. Also apart from chopper gunner, gunship and maybe attack dogs, they are quite easy to avoid if you know what you are doing.
Perks - Stopping power has now been taken out meaning everybody's guns have the same power, and you can now choose between many diverse classes without sacrificing your firepower drastically, and losing in gunfights to anybody that chooses the campy stopping power option. There's no more slight of hand pro for snipers, and no more commando/commando pro. I think that's self explanatory.
Wager Matches -
These are great fun, and are extremely tense if the bets are high. The amount of times you are left screaming in excitement, dread and frustration at being tomahawked in the back tells me that these are going to be a great new addition to the CoD franchise.
The maps are the right size, not too big not too small (spare nuke town) and a lot are symmetrical/well balanced meaning one side does not have advantage over the other just due to spawn points. The spawns are a bit off, but still preferable to modern warfare 2's and Treyarch are always good at listening to their community and so will probably fix it if it shows to be too much of an issue.
That said, there is still the classic call of duty 'bs' that you will get in any title, people surviving too much, you surviving too little, and being shot round corners etc, i just hope treyarch realise that this is still present, and will find a way around it.
Also the theater is pretty cool (yet i'm a bit confused on how to save my films permanently without putting them on my file share.) and is on a par to halo's.
The ranking system and codpoints system is interesting, and you are always surrounded by a vast choice of what to buy with your money, there are also hundreds of personalization options if you don't want to bother buying any more weapons than what you currently have.