Become a MacRumors Supporter for $50/year with no ads, ability to filter front page stories, and private forums.
It all depends on what you're looking for. What might be the best for one person might not be the best for you. Perfect example is the two replies you received already. In the past I would have also said PS Anti-Glare but with the retina display on the iphone 4, I've switched to SGP Ultra Oleophobic and I love it so far. I may try PS when they come out as well but the anti-glare isn't as attractive to me now because of the reduction in clarity. PS has said that their new anti-glare is more compatible with the new iphone's screen but nobody really knows what that means since nobody has seen the new screen protector yet.

For the 3GS, I do think that PS has the best shields but you have to decide if you're more interested in clarity or reducing/eliminating fingerprints.
 
Register on MacRumors! This sidebar will go away, and you'll see fewer ads.