My grade is probably a bit inflated, but it's hard to ignore my bias toward Mike Judge. He gets workplaces. He gets satire too, even if the stuff on display here is more blunt and low-key than it probably should be.
Although it is nowhere near the same level, this film had a fairly evident feeling of being Coenesque, which I consider to be a really good thing. In their hands, this would have been more of a masterpiece. As it stands, it's a gem, but it's really rough. It leaves a lot to be desired, and the humor is a tad too subtle in places, but I still laughed, and was still very much entertained.
As decent as Bateman is, the supporting cast is where its at. Wiig is good, if slightly underused; Judge in his uncredited cameo is funny, as is a riotous Gene Simmons. It is Clifton Collins, Jr, Beth Grant, J.K. Simmons, and (most of all) Ben Affleck and David Koechner who really steal the show. Koechner is really funny, but Affleck manages to edge him out slightly. Everything about Dean is funny and appealing (as a character): his beard and hair, his mannerisms, his outlook on life...he's just this groovy whacked out cat, and it's definitely what Affleck needs to rebuild his still tarnished career.
So yeah, this is a hit, albeit a minor one, but fans of any of the cast (even Mila Kunis is actually fairly believable), workplace comedies, deadpan delivery and humor, or Judge should find something to enjoy here.