SNES or GBA?

[Vitiman]

The only real benefit to the GBA versions is portability. The Advance ports have inferior sound (including a whole lot of very bit crushed voice acting added in) and washed out colours. They also have some added extra stuff, but only SMA3 and 4 have any new levels, and even then SMA4's new levels can only be accessed if you have an e-Reader and the appropriate cards (and another GBA).

I'd go with an SNES if I were you.