first impression is that maps are pretty good for variety. the graphics are maybe slightly worse than MW:2.
with vsync on, i'm pegged at 60fps at 1920x1200, 4AA. (GTX 295, i7 firstname.lastname@example.org, 260.89's)
BUT, the good old COD lag is still there, with players disappearing for a moment, hiccups, etc. i have only played MP so far. also the server browser seems to be somewhat broken.
oh, and it's a total bitch fest about lag and performance, lolz. most challenging part of mp so far is thinking up an original way to complain about the lag.
overall, i'm unimpresseDD.