I just saw it a few days ago for the first time on DVD...
I liked it, but I didn't like the heavy human focus (in some parts I felt like the human romance overshadowed Kermit and Piggy rather than mirroring it) and how Kermit's speech about kids being smarter than trashy programs was cut short XD.
Also, I'm sure it has been talked about before but they seemed to act as if the Muppets hadn't done anything since the 80's movies and the Muppet Show, which took me aback a little. Other than that, and wishing Whoopi had interacted with them more, no downside that I could see. It was spiffy
!