I'd have to go with TSPP because it is so DEEP! If you haven't made it to where you press the left flipper, and the right flipper deploys... you haven't played it enough! Yes, the garage door or vertical upkicker has problems. But name one pinball machine that doesn't. That upper playfield is fun too!
Plus, if you are a fan of the Simpsons... then it really is a no brainer!