Waterworld - there are some deep modes. Great shots and it kind of has a MM layout. I miss the crap out of mine. The deez multiball is great.
2nd place, maybe Gladiators. lots to shoot at, maybe too easy to keep the ball going? And the kicker things above the flippers...not a huge fan.
I played SG at mgc...I didn't like it much, felt cramped and I couldn't hit much. I only had 3-5 games on it though, so maybe I just sucked. Mario I love the theme, only tried it once, seemed okay.