I've had Zagg invisibleSHIELD for both my iPhone 3g and now the Infuse. I've only bought the screen piece for both though. It saved my iPhone's screen on more than one occasion where I was sure it had shattered after a drop. It does leave a piece near the top of the infuse around the sensors/front camera uncovered, but with invisibleShield covering like 98% of that gorgeous screen and the case I have along with it, I figure thats about as good of protection as you can get.
It is not permanent, so you CAN remove it, though I don't if you can take it off 6 months down the road and reapply it later. However, Zagg offers a free lifetime warranty, so if it somehow does get scratched, or ruined, or part gets pulled up accidentally and stuck to a piece of paper (yeah that one happened to me), all you do is go to their
website , put in for a replacement, pay for shipping, and mail back the ruined one.
It's kind of a pain to install, so here's my suggestion: Go to Best Buy or another reseller, pay for the Shield, and pony up the $5 for them to install it. IMO it's way better than any other screen protector out there!! Hope that helps