My complaint is that the matt surface is simply too rough for such a high resolution screen as the Nook HD+. These matt protectors have a rough surface to make them matt, but the size of the roughness needs to be much smaller than the size of the individual pixels, otherwise you get a weird, and very distracting granular effect on large areas of pale colour - such as a book background. The overall effect is quite disturbing. I've used a similar screen protector on a 24" monitor, and they are awesome, but the material really needs to be reworked for a small 1920x1200 pixel device.
On the plus side, the feel of the screen is better, and the anti-reflection works very well. However, it ruined the Nook experience so much, that mine only lasted 1 hour before I ripped it off and threw it away.
As to the 'art' of putting these on... It's a real skill, requiring operating theatre levels of cleanliness. I find it best to 'float' the protector on using a very thin film of soapy water (a bit risky, I know). Even then, you will get the odd spec of dust being sucked onto the screen. I'd advise to leave the odd small spec of dust alone. If you try to reapply, you'll make it worse!