Always had a Zagg on ipad1. Removed it when I rehomed it. Installed a Zagg on new iPad. I noticed additional drag when using a stylus and just was not happy obstructing the retina display.
They say the covers are clear and they are but you still lose that extra punch the retina display provides. I removed the protector and am glad I did.
I have a rotating Targus case so the screen is protected when idle and I use nice'n'clean towelettes for daily cleaning. I'm glad I decided to have unprotected text....it's great!