I love Appetow's stuff, and usually like Rogan (Liked: Freaks and geeks, 40 yr. old virgin, pineapple express, superbad, knocked up, undeclared; Strongly disliked: Zach and Miri; have not seen anything else). That said, I came away from Funny People thinking it was about a 7-7.5. I won't buy it unless I see a version with extensive extras for very cheap; I have no real desire to watch the regular movie again. Parts were quite funny, and I'm glad I saw it, and I certainly enjoyed it, but I didn't leave thinking I wanted to watch it 5 more times like with Pineapple Express, Sarah Marshall, Knocked Up, Superbad, Virgin, etc.
I think that Apetow is falling victim to a little too much creative control, writing, directing, and editing. With DVD technology the way it is, he should work on making 90-100 minute, really crisp movies and just having DVD releases with lots of extras.
ps-for my money, the funniest movie I've seen in the past two years is Role Models. Insanely hilarious.