I've tried many many screen protectors on various devices and I swear by the Spigen products. Since they don't have a Steinheil or GLAS.tR SLIM offering yet, I decided to give the AT&T-branded screen protector a try:
Basic Screen Protector Tri-Pack - LG Optimus G Pro accessories from AT&T
The packaging has a Case-Mate logo on the front, although Case-Mate's website doesn't show it.
Anyway, the cut seems pretty good; it covers most of the glass, up to the beveled edge. It has a cutout in the upper right for the front facing camera and sensors. The feel is not quite as good as Steinheil, but acceptable. I'd consider the clarity above average; while not quite invisible like the Steinheil, it's still pretty clear.
Basic Screen Protector Tri-Pack - LG Optimus G Pro accessories from AT&T
The packaging has a Case-Mate logo on the front, although Case-Mate's website doesn't show it.
Anyway, the cut seems pretty good; it covers most of the glass, up to the beveled edge. It has a cutout in the upper right for the front facing camera and sensors. The feel is not quite as good as Steinheil, but acceptable. I'd consider the clarity above average; while not quite invisible like the Steinheil, it's still pretty clear.