I really liked Sunshine, just as much as Mario 64. The only flaw was the monotonous tropical island theme.
That said, SMS pales a bit right now as I'm playing SMG. Sunshine was more laid back, Galaxy is intense. There's much more variety and innovation in SMG.
On the other hand, Sunshine was more of an exploration game, while Galaxy is pretty linear.
Controls and level designs are flawless in both games.
Edit: Saying that SMG has no good gameplay is ridiculous.
Currently playing: NSMB (Wii)