Personally, I've used the Zagg protector for a number of years, and been very pleased with it. I've used them on 2 iPhones, 2 LG Encores, and 1 iPod Touch. Yes, they are a bit unpleasant to install [I had to try 3 times with my son's Encore before I got it right], but that is the only downside that I've found. As for the feel, I found that once I got used to the "rubbery" quality, I found it hard to adjust to a plain screen protector. I'm a person who likes to fiddle with things, and find the rubbery feeling very enjoyable to toy with, as opposed to the smooth hardness of your typical screen protector. Also, the texture didn't create any issues with viewing the screen, it was always nice and clear, and I never experienced any trouble using the screen, it was always very responsive to finger movements.
I'm not saying the Zagg is the best protector out there, but I've been happy with it since I first discovered them. Since getting my iPhone 4s, I thought to perhaps try the Bodyguardz protectors, they seem comparable, and cost less, too. However, I'm using a LifeProof case at the moment, which has a built-in screen protector, so I don't need anything else at the moment.
YMMV

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Frank