I loved it in the theater, watched it again here at the Embassy for a showing (kids night), and will buy for a birthday present later. I grew up with the muppets and my boys have watched the first 3 seasons on DVD with me. They may not get some of the references, but they still get the slapstick humor!
To me this Muppet movie was quite different from the others. I was surprised at how much singing there was.