Just got one a week ago, they are GREAT!!!!! The only thing is that some cases don't like them and make them want to come off, but since they are static, they go back down and NEVER any bubbles!!! wonderful.
Ive got the invisishield HD on my 4s and its great. Couple things. Dont mess with it after you put it on. Youll have bubbles and stuff but let it set overnight and theyll be gone. Also they get "dents" pretty easy cuz theyre so thick. Its like gouges in the screen from keys etc. Now as far as feel goes the HD's are much better than the earlier zaggs. The rubbery feeling isnt there anymore but dont use windex etc to clean them or theyll develop that rubber feeling and cloud.