Went and saw this last night...it was alright.
Had a few hilarious moments, but didn't keep my laughing throughout like 40-Year-Old Virgin or Knocked Up. James Franco was hilarious and should definitely do more comedy. The cell-phone scene in the woods was my favorite part of the movie. Rogen wasn't as funny, but still was pretty good. Didn't have enough Bill Hader as he only appears in a 5-minute flashback at the beginning.
If you liked 40-Year-Old Virgin, Knocked Up, or Superbad, you'll probably enjoy this, maybe just not as much as those. Same kind of humor, just not as much of it.
I'm not really interested in this one. I might end up seeing it if some friends want to go, otherwise it doesn't look like my type of movie.