If it's the characters, I'd probably choose Mario.
If it was the games, it would be a lot harder choice.
Donkey Kong country for the SNES and it's sequels (Especially 2) were great games. However, after the 3D era came, Donkey Kong became horrible, while Mario improved dramatically.
defiantly donkey kong,mostly because his the underdog of gaming,i meen without him jumpman(or mario) wouldnt even be here right now....so go donkey kong!
For the games, Mario, even though without Jumpman there would be no Mario, I like Mario's games a LOT more then Donkey Kongs... Super Mario 64, to D.K 64... to me thats 'nuff said. That and nothing can compare to the classics of super mario bros 1 and 3. Though D.K 64 was ok to me Mario 64 is waaaaaaay better. For characters still Mario. I mean he can burn stuff and that in itself is awesome.
Donkey Kong Game on Nintendo 64 was way cooler. The Opening rap was awesome. Its just way cooler. Then there loads of mario games. Like Mario tennis and golf. and there pretty cool but Donkey kong is in most of them. I like them both, but i have to say DK is better.