I use Sony Reader and I like it very much. There are few things to consider when buying a e-reader:
1. Battery life- very very important
2. Capacity, how big can you expand the memory
3. Does it have capability of showing photos, playing music-its is very soothing to listen to some music while reading e.g. in a plane
4. What is the technology they use for their screen. Some screens will mess your eyes.
5. Can it connect to the internet, does it have organiser, calender etc.
7. Charging from the mains capability. Some e-readers have to be charged only through USB in a computer (hooking on pc-cumbersome). Otherwise you have to buy a charger.
PS-I have a uneasy feeling that you have used Sony e-reader images to advertise for cooler readers.