Started playing multiplayer today. I have devoted 6+ days in playtime into each CoD since 4, so I am a big fan. I'm sorry to say, this game is terrible.
The maps are horrible, you can't see shit, and when you do see someone, it's way too late because of lag. There are way too many buildings and high ground, so much camping and sniping going on, it's ridiculous. With that said, there is more gunplay, which is good.
UAV/Sat Com has been gimped beyond recognition due to the fact the default perk of off the grid makes you invisible to it - who will EVER turn that off? I love that it can be stacked and three gets you a blackbird-type UAV, but again, it's a pointless killstreak since everyone is immune to it.
The squad points system is only to reward hardcore players - if you don't play a lot, you are fucked and are fucked for at least the first 20 hours of MP. Since I game with people I work with, who don't play as much as I do, this is a gigantic turn off for them.
Overall, my first impressions are not great. I really think Infinity Ward is a disaster, I am eagerly awaiting Treyarch's next entry for the time being.