I am using JOTO non-glare screen protectors on my S3 and SP3. They are a PITA to install with no dust or bubbles because of the size of the screens, but once installed, they turn the glossy glass screen that is unusable while traveling in a vehicle on a sunny day into something that is quite usable. They also greatly reduce fingerprints and dust and I like the feel of the stylus on them. Probably not as protective as tempered glass, but they do what I need them to do.
I have Stickerboy skins. Pricey, especially when compared to Decal Girl and some of the others, but I got the sets that include the keyboard protector pieces for the Typecover and I'm happy with the skin sets. The material is pretty thick.