This is an interesting question. Back in the eighties the only system I had was an NES. Super Mario Bros. was one of the titles I used to pull out to support my console's superiority against my SMS friends. I'll admit, it is hard for me to put nostalgia aside when asked this question. But I'll try.

23 odd years later, I now own both systems and collect games for each console. I've played through Alex Kidd and give it kudos, but I still feel Super Mario to be the better game. As said before in this thread, SMB is a little more "direct" and paced a bit better than the methodical Alex Kidd. And that is why I choose SMB. I like that style of game play better.

I know this is a bit off topic, but if you throw WONDERBOY in the mix you've got a whole new ball game. That title in my opinion goes toe to toe with SMB and destroys HUDSON'S ADVENTURE ISLAND!