I like the ones sold right here in the crackberry store. 3 to a pack for 12.99 or something like that, they have a sort of gel on the back that if placed carefully doesn't trap any bubbles and doesn't require any tools for smoothing... they go on quick and easy, and come off clean. They reduce glare but have a smooth finish, and I give them an 9/10 for clarity. Let me put it this way you wouldn't notice one unless you were looking for it.
I like Zagg for the body armor, although I've been using Case Mate Hybrids (make it chubbier, but it makes it a bigger device which I like...) but for the SCREEN:
Zagg.. but I found that I also like the ones you get off ebay (10 for 2 bucks sort of thing), because I sometimes mess up on them or I like to give them to some friends or whatever.... So Both! Zagg and cheapos from ebay!
i have a Zagg on my 9700 and Ghost armor on my 8900. the fit of the Zagg doesnt cover both beveled edges of the 9700 screen perfectly so it ripples a bit on the edges. and their application kit sucks. i would get the Ghost Armor again if the Zagg scratches.