Gorilla Glass 3 = no screen protector for me! Wife has a Zagg on her S3 and it feels bumpy and sticky when I run my finger over it. Keep the phone in my pocket and it sits on my desk undisturbed during the day (for the most part), so my exposure to scratches in somewhat minimal. Also I don't live near a beach, so sand is not an issue. Sand is EVIL when it comes to screen scratching!
BTW beer, sun and hot tubs are an evil combination when it comes to your smartphone's ability to swim, but I digress...