My wife is a power reader, one or two books a day on weekends, and she is a LONG time user of hand helds (Palm). We did a lot of research, tried many devices and talked to friends with various devices.
Eink was rejected, its fine if you have light, but too often my wife likes to read without a light, and much prefers a backlite display.
Nook vs Kindle took longer to decide, but in the end she was firm on her choice of the Nook Tablet.
Initially we were thinking almost 100% ereader use, but from day one she was playing with the Nook and trying various options, and so far is liking Netflix and Pandora, as well as a few games. She is very happy with the Nook Tablet, but I am NOT happy with some of the proprietary items like the non standard USB that requires a Barnes and Noble cable, AND chargers, or the way some various playing well with others is blocked.
BEWARE of Bejeweled, DRM requires a constant wifi connection, you can't play it in the car, on a plane, etc. totally Fubar useless.