I had to say goodbye today to my second Kobo GLO HD. It developed a thin line running about a cm in from the top left down the screen. I bought my first GLO HD on the 25/09, the first one developed exactly the Same split within four days, this one last four months.
Luckily Argos gave me a full refund so for now I'll stick with my H20, maybe the plastic frame (although my GLO HD was in the official kobo case all the time) makes them more susceptible to this crack but even so it's strange I got two with the same problem.