I just watched it. I liked it. I thought it was pretty funny. There were several parts where I laughed pretty loud. I think the banter between Franco and Seth is what is the funniest, not necessarily the material. I also liked a lot of their music choices, of course they played White Stripes (twice!) so I guess I am a bit biased.
It's not the funniest thing I've ever seen; of course not, but I enjoyed it. So I think Kristen and Joan you two should watch it yourself and see if you think it's funny or not. So far all us who have seen it ourselves it was fairly enjoyable.