The PS Anti-glare is by far the best screen protector i've used. I used the Zagg as well and didn't care for it. The Zagg is rubbery. your finger won't glide across the screen. Also with mine i noticed little nicks all over the protector. Remember, this is all MY personaly experience and feelings.
The PS Anti-glare is awesome. It is incredibly smooth, no rubber feeling, and the best part is very little oil and fingerprints. The only downside is that the protector does take away a little from the retina display, but i would imagine the Zagg one would, too. Also, it is a static cling, no adhesive or wet install.