I just played through the game last night with a friend of mine, he was about 2 or 3 hours in when i joined at about 10:30... 6 hours later, after about 10,000 bullets per gun and too many deaths to count, we beat the game, and while i had some minor gripes, they were just that, minor, the game is indeed "frackin' awesome" - though i can see how it could get too frantic for some... the frenetic pace just made it that much more addictive to me, that "one more check-point" mentality that made me stay until 4:30 AM to finish it off (that last boss is a pain in the rear!)
terpfan - i agree the take cover command was sometimes not good, my personal gripe was its reaction, i never did figure out the finer points of it, but overall it worked well
my only other gripes with the game are its length, though there will be a GoW2 i can guarantee that, and some minor technical gripes (whats up with the sniper rifle not forcing you to reload because you are zoomed? really sucks in the heat of a battle to forget to unzoom, reload, and rezoom, only to fire and realize you forgot those steps)
my favorite moments: both players in co-op mode chainsawing the same Locust Grunt (and no, i don't know if we chopped him into 3 pieces, both screens were covered in blood and i couldn't see). Me dying on top of a Locust Wretch with my chainsaw going (

lots of blood!) and that last sweet headshot on the final boss. - Plus the dialogue in the game just rocks, the writers deserve some major props, and whoever decided that the reload feature needed to be skill based gets mad props from me!
EDIT: oh btw, the Corpser (the spider things in the commercial) goes down right nice and pretty too, that boss fight was pretty fun