I have had to return my PW2 which I got from John Lewis in January because at mid light levels the lower left screen was in shadow. (full light - the lights were working but hurt my eyes)
Not sure when this happened - I rarely read with the house lights off and I also have a NOOK STG which gets used a lot. But the good news is that I now have a 4GB PW2 instead of the 2GB.
. (Altho' John Lewis still advertise the PW2 as having 2GB)