korra is powerful too

I think when neither of them are in the Avatar state, Korra is more powerful because she's older and more aggressive. She won't quit until her enemy is down because she's fiercly determined. The only advantage Aang might have is, he waits for a good opportunity to strike, whereas Korra just goes for it.

My bet in on Aang, but I haven't made up my mind completely, yet; there are still two books of Avatar: Legend of Korra left to go. At least, I assume there are...

Aang is more rounded and open minded, so he can master more stuff.
and don't think i'm just talking about elements. i'm talking about everything.

navvia said it already aang waits for a good opportunity to strike and thats the key in a fight youre chances are way better if you do that instead of just going in shooting fireballs like a lunatic