Before you say this is cliche read the conditions:
This the Aang at the end of the legend of Aang.
This is BOS Ben 10 (Prior to master control).
However Ben 10 have access to all the 10 original aliens.
But in the second scenario this is Ben at the beginning of Alien force.
1: EOS Aang VS BOS Ben 10.
2: EOS Aang VS Ben 10 (Alien force).
Who will prevail?