My advice: none! Both my ATIV S and new 1520 are without screen protectors and I've been problem free. I trust gorilla glass to remain scratch free, and all I have to put up with are fingerprints on the glass which are easily wiped off.
Well..go with tempered glass, or some plastic one..it doesen't really matter. If you phone fall it will break, screen protector is just for scraches.
I use some mix between plastic and glass. Forgot the name but it's ticker and more durable then plastic,but not stiff like glass.
Only problem i have with it is soetimes (and untill you adjust) it's sticky. Hard to type.
I just got this http://www.amazon.com/Nextechn®-Pre...ag=hawk-future-20&ascsubtag=UUwpUvbUpU3118728 and it works as well as any other tempered glass protector I've had before with the same caveat about fit. And contrary to the above, it does help if you drop your phone screen first, takes the impact and leaves your phone undamaged.
Highly recommend looking at Martin Fields. Fairly easy application. Been using them for years on all my touch screens (iPod Touch, Surface Pro, 1520.3 etc).
I agree, definately go with a tempered glass protector, unfortunately do to how the device is shaped, the edges will lift up on all tempered glass protectors, but really it's only noticeable when the display is off, but its completely invisible and feels much better than any other kind of protector when used.
Highly recommend looking at Martin Fields. Fairly easy application. Been using them for years on all my touch screens (iPod Touch, Surface Pro, 1520.3 etc).
Could you show how martin fields protector looks on your device? I love their product but totally hate having those lifts on the sides that is common on regular protectors and tempered glass as well. I'm using a brand called Capdase right now and it's cut smaller than the rest of the protectors I've seen. But because of that cut, there are no lifts on the edges. I still would want to go back to using martin fields though.