I saw a showing last night with my brother.
It was very "meh" to me. It was watchable and I had a few laughs, but it was nothing that hasn't been done before.
My ten year old brother even admit he was disappointed.
If you like Shrek, go see it, you might like it more than I did.
Edited to Add: One thing I really did like were the princesses. They were actually quite amusing and I didn't realize until after the movie who played them, so that just made me like them more.