I did get the game today.. was in-stock everywhere, as previously said, it's not got a big hype as of yet.
Love the single player, even though it's linear, I don't feel constrained to a single area of the level. Haven't played MP that much yet, but it's really smooth with all that havoc going on.. some really good netcode!
One gripe is that on single player, the sound effects seem to stop and loop sometimes.. e.g. the Blizzard Level - the wind/snow sounds would stop for like 3 seconds and play again, quite annoying but passable. Same happens with the dialogue.