Shrek is a lot of fun for awhile but the mini-playfield (great fun at first) absolutely kills its long term playability. Can't remember what the setting is called that makes it harder to get up to the mini-playfield (captive ball set to hard?), but if you get it turn that all the way up before you even play a game. It's still not enough to save it from becoming monotonous though, and you can't turn it off completely because it takes up too much real estate. The Smashmouth song only plays for the first 15 seconds or so of the first ball, so that never bothered me at all.
Had one, enjoyed it, sold it fairly quickly. Just thinking about it makes me want to play again though...Shrek is one of those rare games that I wouldn't buy it again but I wouldn't recommend against others buying it because I enjoyed it so much while it was here.