i've used the invisibleshield since the first gen iPhone in a bevy of ways (full protection, screen only, etc...) depending on if i wanted to use another case or not. this is by far the best screen / full body protector available for idevices. holds up like a champ and does a hell of a job. this is going to be perfect with a front and back and a bumper for the iphone 4. the same glass used to make helicopter windshields and the same material used to protect helicopter blades... i'm guessing the redundant reinforcement here is going to be a win.
for those of you wishing there was more than one, please keep in mind that the point of the invisibleshield is to not really need more than one. they don't get all scratched up themselves like other screen protectors and if something does happen to it they replace it for you no questions asked. and don't worry about the "wet" install, not only does it make it super easy, but it creates 0 water damage issues.