That proves nothing. The Inter squad that Benitez inherited was full of Mourinho-type players that Benitez wouldn't necessarily have signed, due to the differences in the way that the 2 managers set up their teams. A few good players left and the remaining ones may or may not have been suited to Benitez's style. Therefore you simply cannot say that Mourinho is better: he had 2 years to shape the squad to suit him. Benitez had just 6 months and hadn't been able to sign any first team players at all (leading to him asking for support in the january window); during that time he still managed to win 2 trophies though.
But he also got a champions league winning team out of champions league qualification position. You usually say that a good manager doesn't need time to improve but when it comes to Benitez at Inter you are talking about not his type of players etc, which is which? Now if Benitez is that good, I don't understand why Chelsea is not keeping him, or at least City should try to get him isn't it?