3 main reasons why
like Sony 300:
1. E Ink screen
- It has a great reading screen, great clarity and contrast. I can read for hours with no eye starin.
2. no SD card slot
- with 350+ books, there is still more than 50% memory left. FOR ME, this is more than enough, and I will only have around 20-30 books on the reader anyway. I can't read 700 books simultaneously 
3. no Folders support
- Collections is fantastic!!! I can have 1 book in memory and have it in 4 different "folders" without eating up memory by putting it in different folders.
One man's trash is another man's treasure.
Congratulations on your choice, you will love it. Any of those other readers listed would have been a fine choice as well and I do not think there are any readers out right now that you would be remiss to buy at this level.