I'm finding two things annoying at the moment.
I'm getting a bit of an 'under glass' effect when reading in certain lighting (especially at work) where I can tell that I'm looking through a layer or two on top of the eInk. Sometimes I'm more sensitive to it than others, but I find myself getting distracted by it while reading sometimes.
Another thing I can't seem to get used to so far are the fonts on the PW. The sizes are 'off' when compared to my Touch and K3 where I had settled into a perfect size and the PW is either too small or too large and I can't seem to settle in when combined with line spacing that's a bit different too. I'm sure I could get used to a new 'perfect setting' given some time, just not sure I want to. I wish we weren't limited to specific sizes instead of a slider for font size on these devices.
The light isn't as big a deal for me as it is for some so I'm not sure, I might just go back to my Touch or K3 and save my $140 for another day.