Both are great games, and better than Ocarina of Time.
I give the nod to Twilight Princess though. It is basically "Ocarina of Time 2" and improves on many things that made Ocarina itself a mid tier Zelda game.
If you are looking for a challenge though, Skyward Sword is the harder game. Not because of bad controls or anything, the motion controls worked great. It is just structured to be a more difficult experience than past Zelda games.








