I have both the Sony 650 and the Asus Transformer. While it's possible to put a lot more apps on to a tablet to change the reading experience, there's no way that I would rely on my tablet as a reader. My 650 is like reading a book. The tablet is like looking at a monitor. It's too heavy and bulky to curl up with it and the screen simply doesn't display text as well as my reader does. It's great for internet look ups, full color support, note taking at conferences, especially if I have the PowerPoint slides in advance, and watching video. It's horrible for reading novels.
Just a note to avoid confusion: When Sony came out with the PRS 600 and 900, they chose to put a touch screen overlay over the eink display. The result was blurred, somewhat unresponsive, and had excessive glare. The PRS 350, 650, and 950 use an infrared grid over the screen to provide the touchscreen. This means that the screen is as clear and readable as all of the other Pearl screens on the market. Unless you can see infrared beams, you will not notice any blurring etc. on these latest model. For reasons that escape me, Sony chose to call both the 600 and the 650 "touch edition," and there are still retailers selling the 600s and 900s. You need to be very careful to make certain that you purchase the correct model