I have used Zagg invisashields on every touch screen device I have owned (wish they made one for my ultrabook) and they always keep the screens in perfect shape. sure they are a pain in the butt to install but its not like I am doing it every day. I had to have one replaced on my Galaxy Tab 10.1 after 6 months and when I took it the screen was still like new.
This time on my S4 amazon didn't have the zagg ones so I went with Armorsuit. Same basic design though. It doesn't have a rubbery feel to it very smooth works great with the touch screen