My fingers are no less oilier than previously, and as a result I have not had reason to change my mind about touch-screens.
There's also tactile feedback. When I press a button, I know without concentrating that there's a definite outcome on the screen. With touch-screens, I feel the need to concentrate on the screen to see if the device has responded to my touch. I find that I can get away with being mentally lazier with buttons, if you get what I mean....