I have tested all the above in the stores. My first reader was/is the Sony PRS-300 and it still works. I wish Sony had the buttons like the 300 uses, for the T1 instead of the touch screen. I am still trying to get used to using the touch screen instead of using the T1's buttons.
It is quite a step up from the 300 to the T1 and I prefer it. Much clearer screen and easier to read.
I could not do a Kindle because I did not want to get tied to Amazon for books.
The con: The T1 has to wait 10 minutes to go to sleep or power it down, if I am reading and I have to toss it back into it's case real fast. I am constantly powering it down to put it down when reading while being a passenger in the car. Otherwise the screen will get touched and pages will flip.
I do not need a keyboard and I think there is a touch one on the Sony, just have not used it yet.
PRS-T1