Simpsons is a MUCH better game. Family guy is funny but the playfield stinks. One ramp, hidden pop bumpers. A mini playfield that gets boring after 3 plays (physics are nothing like a real table. More like a cheap childrens pinball you get at radio shack). Probably Lawlor's worst design.
Simpsons is DEEP, tons of shots. Upper playfield is small but actually challenging. Stackable multiballs and modes, bunch of wizard modes. Springfield mystery spot. It's really no contest IMO.