It's Zelda, and it is nOt remotely close.
It is significantly better in the NES
Better on the SNES
ABSOLUTE OBLITERATION on both the N64 and Gamecube.
Till about a week ago, it was Mario by a nice margin on the Wii, but after SS it is at worst a tie,'and more than likely a Zelda win.
LA is better than the Mario La d games, so there is the GB
GBC is easily Zelda.
GBA is definitely Mario
DS is a toss up (all 4 games are ok, but disappointing)
3DS is Zelda just because of OoT, but if you don't count that, then so far Mario by default.