There's no way you can really compare a gamepad to a touchscreen. Just the fact that you have a physical response is a huge boon. Most of my screwups are hitting grab/d when trying to use my sword. Then again I have an ipad2 and even with large controls they're still fairly small...
Not saying this will give you an advantage, but even after years of having touchscreens around I still can't stand them. Like I said, it's just the physical presence of a button that helps you know what you're doing.