Loved, loved, LOVED "The Muppets." I actually went back to see it again the afternoon after my first viewing just because it was such a delight. It was clearly made by people who have a deep, deep love for The Muppet Show, and any fan of the show and the first three movies should love this. Lots of laugh-out-loud moments, and the new songs are lively, well-written and catchy as heck. It's a sheer delight, and I hope it leads to more Muppets projects in the same vein in the near future.
A couple of notes--not quite spoilers:
About the only prominant cast member from The Muppet Show I could think of who didn't have at least a cameo appearance was Kermit's nephew Robin. Given the almost obsessive attempt to include as many Muppets as possible, the omission seems odd, and I'd love to know if Jason Segal has addressed the issue anywhere. Is it possible they thought that Robin's naive/newbie vibe was too close to what they wanted to do with Walter?
If you listen to the full-length version of Tex Richman's rap song "Let's Talk About Me" off the soundtrack album, you'll find several additional verses, not included in the movie, that fill in Richman's background and why he hates the Muppets. It also makes a few of the lines of dialogue in the film make more sense. I can only assume the full song was cut for the sake of length; I hope that the sequence was shot, and that it gets included as a bonus on the eventual DVD.
Speaking of DVD--when, when, when, oh when are we getting the final two seasons, or any of Muppets Tonight?