I saw the movie last night, and I'm still trying to wrap my head around it. It was such an amazing experience, actually seeing a Simpsons movie, and it being like a "best of" in terms of past eras. I gave it a 4.5, and I left the theatre knowing the movie will only get better in rewatches.
The plot was done very well. A lot of the time, it will feel like an episode didn't devote enough time to flesh out a plot and give it a logical conclusion, but we have everything in here. We see different sides of Lisa and Bart (making them look more in character than they've been in years), Marge has an understandable conflict, Homer gets to be a hero, and Maggie is funnier than she's ever been. The only drawback is past (and probably future) episodes where Homer is selfish or Marge considers leaving Homer pales in comparison to how it was done here. I also like that they set things up like the sinkhole and the motorcycle thing to be paid off later.
The length was a bit of a problem. Because it was so short (and they spent some time away from the town), we didn't get to see all of Springfield. I was kind of surprised at how many sets/environments were absent. The church was there (was it just me or did it look smaller?), but the inside of Springfield Elementary, the Kwik-E-Mart, and the power plant were all kind of shafted. Then there are the characters. It's nice to try and spot who you can recognize, but when some characters get lines and others don't, it leaves you wondering. Why does Cookie Kwan get to speak while Jasper, Sanjay, Sherri and Terri, Kirk, Miss Hoover, and a dozen others don't?
I'm actually wondering if people like Moe/Wiggum/Comic Book Guy/Cletus were given larger than average roles because Hank Azaria was sort of the odd man out (Harry Shearer got plenty of lines as Flanders and Schwarzenegger). Did they want to balance things out or something? Speaking of voice actors, it was great that Joe Mantegna got a little something to do as Fat Tony. I was hoping he and Jan Hooks would be in the movie since they're my favorite recurring actors.
I've probably got more to say about the movie, but all in all, it was funny, beautifully animated, heartfelt (loved that they used "Close To You"), and a wonderful experience to this longtime fan of the show.