I've had a NST w/Glowlight since about a month after it launched. Unfortunately the rumors are true, this thing is just a bit fragile with respect to the light. I carry mine with me most days protected in a courier bag and wearing the B&N leather cover designed for the NST/NSTG and mine has now developed a 2mm long hairline "light crack" too without it ever getting hit or dropped, etc.. Luckily it is not super annoying as it's near the top of the screen..
I have the accidental damage policy I am kind of tempted to see if they'll give me a new one.
Honestly I feel like this thing was a mistake anyway.. the contrast without the light is more annoying then I expected. It's a lot worse then my old e-Reader (Kindle DX Graphite) in certain lighting conditions, and the GlowLight looks really blue when you use it in a room that is light but is dim. (Conditions that you would not need a light with a regular NST are the worst case for this reader.) I ride the subway and I see people with regular NSTs and Kindles and their screens look great in that dim light whereas the Glow either looks too low contrast (no light) or blue and obnoxious (with light). In total darkness the Glow is great though.
The idea of the light is great it is just not implemented well.. I am going to give the Kindle Paperwhite a try.. if that doesn't work I'll return that and go back to a non-lit E-ink reader.