There is a lot of good stuff in The Simpsons Game. For example; Bart, Homer, Lisa and Marge all have interestingly different powers, the plot is typically funny and lots of familiar characters get a nod. As a game, it's arguably one of the best we Simpsons fans have ever had.
However, I can't give more than 3/5 due to the lack of replay value. Once you've completed the game, that's pretty much it. For example; there's no option to replay levels with different characters, no extra powers, no scores/times to better and no alternative skins.