I've tried a few cases here and there, but always come back to uncased with powersupport crystal front, bodyguardz back, and lucky labs side.
It works well, and I don't have any scratches, but I've never dropped it and it's always had it's dedicated pants/shorts pocket when in transport.
The phone feels better without a case and there's really no case to protect the screen from fracture. And the back glass is replaced by Apple for $29 anyways, less than the cost of many cases. So I figure the case doesn't really monetarily protect the device.