You need to use different skills for both. No matter what, you need your shooters. No matter what, you need your PG. And you especially need guys who can pass and you need guys who can get in the paint.
In a fastbreak offense, you need ball handlers who can make their decisions much faster and execute quickly. In a fullcourt, you need either patience or someone who can break down the offense whether it's from posting, driving or from passing.
Not one is better than the other and one doesn't require more skill. In my opinion, the better the players you have, it doesn't matter which type of offense you run.
“Whenever I’m about to do something, I think ‘Would an idiot do that?’ and if they would, I do NOT do that thing.”- Dwight Schrute