My son wants to upgrade from his Canon SX20is, and is looking at the Nikon D3100 and the Canon EOS Rebel T3.
"It is not so much how you manage the successes but how you withstand the crisis."
At that level of camera, the actual camera itself doesn't matter. Both are just as good as the other.
Maybe think of it in a bigger picture and committing to a system for the longer term.
I use Nikon and Leica for work, but its out of history more so than any other advantage.