Zagg Invisible shield for me (screen only). I just let it "cure" overnight (I couldn't keep my hands off my phone for 24 hours!) and it's worked great for me.
I've also got one for a GPS navigation unit in my car which has held up fine in heat/cold temperatures.
I've used them on multiple devices and they've survived my cat trying to use my phone (good protection vs claws).
(No, I'm not getting a kickback from Zagg for this endorsement.)