I used to have the Sony prs 300 which was 5 inches. Now I have a few 6 inch kindle devices and much prefer reading on the 6 inch screen. I have a phone with a 5.3 inch screen and that doesn't feel as comfortable to read on even when you discount the backlit screen. The size matters to me too. I guess 5 inches could be good for someone new to e-reading.
Another thing to consider is the amount of sideload books you have. I bought a Kobo glo last month. I put a lot of sideloaded books on it, unfortunately the kobo glo didn't allow you to customise your sideloaded books. Apart from changing the font and size, you couldn't do anything else with sideloaded books like changing margins, line spacing etc.
The dictionary on the kobo is pretty woeful compared to the dictionary on the kindle.
Last edited by shanghaichica; 11-11-2012 at 10:52 AM.