I bought the Zagg Invisible Shield within a few days of getting my Droid in November. I've had zero problems with it discoloring or peeling off.
My primary reason for using it wasn't screen protection. I like it because it seems to resist smudges better.
I have tried Zagg on three different phones. Two with just screen and one full body. The full body was fine for a while but the corners did eventually start too peel off from normal use. Not installation error. As far as the screen the feel was always tacky on all three from the get-go. And two of them picked up permanent stains from who knows what. And one was actually had a yellowish tint when I took it off. And I am very anal about keeping my screen clean.
Hey if you like 'em no worries. I'm glad you found a product you like. Just not for me. Or a bunch of others as well.
Invisisheild is by far the best screen protector out there. It completely stops the smudging you get when your hands aren't the cleanest. it protects the screen from random things scratching it while it's in your pocket. and compared to any other screen protector it goes on with ease. so easy they let the minimum wagers at best buy do it for you. the only thing i've ever found to be a problem was my first droid **** the bed and i needed a new one. when i peeled off the sheild it was stained from oils on my hand over the last seven months. now i didn't notice the stain while it was on, just after i took it off. So thanks to an awesome lifetime warranty, i called zagg, and they sent me my new one. no other company does that.