Are those pretty decent screen protectors? I had a zagg invisibleshield on my 3G and liked it but this sounds like it's better for high resolution screens. Have you used this screen protector in the past?
Power Support for the previous iPhones were awesome screen protectors. My original iPhone has had the same one on it for almost 3 years (it has just finally started to show some minor signs of wear) and my husbands 3gs one was on it for almost a year and still looks great. Hopefully the ones for the iPhone 4 work as well, I'm not a big fan of most other screen protectors because you can usually feel that it has a screen protector on it, and with the power support ones it feels just like the actual glass.