I've tried both the ClearTouch Anti-glare and the ClearTouch Crystal. Prior to this I'd also tried the one that comes with the BodyGuardz body protection kit and the ScreenGuardz HD. My favorite of all four is the ClearTouch Crystal. It gives the screen a glossy look - colors look richer and more vibrant, while the feel of the surface is identical to stock. This was very noticeable when comparing it to the Anti-glare one, which made the images look slightly hazy. Also, I don't use my N810 much outside so the anti-glare characteristics wasn't a big selling point for me but obviously how you're going to use yours will be an important factor in your decision.

A couple tips for installing your screen protector - don't peel off the backing all the way right off, peel off just enough to install it, then lay it down on the screen and peel off the backing as you go. You will need to adjust the screen protector to get it to line up perfectly and fit within the bezel, as the ClearTouch ones are cut perfectly to size. Also, as you're laying down the protector, look for dust that snuck in, lift the protector off of the screen, and use some Scotch tape to remove it from the adhesive side of the protector, this may take a couple of tries but works pretty well.