Diablo
Over the last week I hit with the Diablo Tour and the Tour o3 mid and I was a bigger fan of the Diablo. While there was certainly a bit more pop with the o3, I liked the control, serve and spin better with the Diablo. I think you'd be happy with either racket - they felt very similar to me. In the end, I was won over by finding the Diablo for $53.99 at Dick's Sporting Goods. Even thru TW - the o3 is $50 more.
I'd love to hear some other opinions too.
Good luck!