As a Broadway enthusiast, I'd like to offer my opinion. I used to be all for musicals based on movies, but beginning in, say, mid-2005, that genre has been overkill. However, I'm excited for the Shrek musical, particularly since it boasts having some fairly big-names stars (Brian D'Arcy James and Sutton Foster; more on her in a bit) behind it. I could stand to have a bigger-name composer/ lyricist team behind it, but from what I heard in the videos that Jacobsnchz posted a link to (seriously, if you haven't already checked them out, do), the music seems pretty good. I don't know, I'm a little nervous about this because so many movie-based musicals that I've been hopeful about have ended up being critically panned. But I'll continue to be optimistic about it.
Now, back to Sutton Foster. I saw her (and briefly met her) in Drowsy Chaperone, and she's quite possibly my favorite Broadway performer in recent years. While she's very talented, I think she's a bit too sought after. I mean, Drowsy and Millie were fresh ideas, so there's nothing to compare her performances to. But after doing the musical versions of Young Frankenstein and now Shrek, she's left to be compared to Terri Garr and Cameron Diaz, respectively.
So, again, both Sutton and what I've heard of the score keep me optimistic, but I'm still a little reluctant that it will be panned by critics.