If you love that SD card, stick with the Nook. While the lighting IS better on the PW than the Nook, it's not so much better that I would do without the SD card. As far as the text, the Nook still wins, in my opinion, because of the choices of fonts and sizes but overall, it is still better than the Kindle Touch. The text has more contrast than earlier models, which helps. You lose some of that contrast when you turn on the light - not an issue for many.
I bought this PW for my Mom. I have a reading light and really have no need for the glow. My Mom, on the other hand, doesn't have very good lighting and doesn't want a reading lamp (just a table lamp), so I got her a PW. If I had known that B&N was going to drop their price to $119, I would have bought that instead because I prefer to side load onto the card. Fortunately, most of my B&N purchases have no DRM (or easily removed), so that I can put it on her Kindle (I have 2 kindles and a Nook).