I am completely careful with my electronics and always have cases with covers on the iPads. Unfortunately, no matter how careful I am, only cleaning the screens with iKlear and clean microfiber towels, I would still get micro surface scratches. I've had my iPad Air for over a month and already can see two micro scratches - can't see them unless holding up to the light and at an angle, but they are there. My last IPad was pretty perfect when I traded for an upgrade. This iPad came with two tiny spots/scratches on the back and now I have the scratches also on the screen.
I am really pretty good at installing screen protectors and put one on this morning. So although the scratches are still underneath, at least I can't see them.
As for the glass screen protectors, I have the Bodyguardz glass protector on my iPhone and love it. Unless someone comes up with a thinner version, I wouldn't want the glass for my iPad. Right now I have the Tech Armor clear. Usually, I'm all about Power Support screen savers but figured I'd try the Tech Armor due to recommendations from this forum along with the PS delayed release. So far, so good with the Tech Armor - installed nicely and absolutely no degradation to the clarity.