I did the same research, for the same three ereaders. Although I did not really like the plasticky cover of the Kobo.
I used to buy books from Amazon, Kindle but did not want limit myself just to one store. So I got the Sony PRS-T1 and LOVE IT!. What I really like is first dedicated public library icon which takes me to my local library. So super easy to get free books! Once you set it up, you go directly to your library and browse or hold titles. What I also really like is that it has the touch screen to flip the pages as well the buttons. I like that option. I use the buttons most of the time but reading in bed, while hubby sleeps, I flip the pages with the touch screen
. I purchase books from Kobo (90% because they have great deals and discounts) and sometimes from Sony ereader store. Never thought I would borrow so many books. Since I got this one for Christmas, I have read 5 or 6 books! If you decide to get the Sony, get the cover with light. So cute and handy, its like a little book cover and light is already set up, just fold it over your screen.
Love it, love it, love it.