Galaxy, no contest.
Sunshine was a huge step backwards compared to 64, luckily that was rectified with Galaxy. Sunshine's level design was uninspired and uninventive. All thanks to FLUDD, which made any type of real platforming mute. Any and every problem was solved by just hovering over. The best levels in that game, by far, were those where you didn't have FLUDD.
64 > Galaxy >> Galaxy 2 = 3D Land > Sunshine