I'd imagine with the smooth, curved plastic back, you might want to pick up some kind of skin to help you grip it. Other than that I doubt a little sweat will hurt anything, especially since it's like a faceplate and there shouldn't too many holes leading to the more sensitive components on the inside. Might get a little dirty, but should wipe off easy.
You might also consider one of the many leather cases out there. They don't "stick" inside the pocket so badly, but they do protect the phone. Unfortunately, they'll add more bulk than a silicone glove, but they're less bulky than a man purse!