Ok David, thank you very much. After some days I think I like the kobo glo. It's not mine actually, it's a gift for my mother, but I have been testing it in order to help me out in making a decision about what device to buy for myself: Kindle paperwhite or kobo glo. What has restrained me so far to get a Kobo are: 1) the annotation issue, but I saw that you can make up to it with calibre and 2) the battery life (as far as I know the kindle has a longer life).
If the difference (of batteryl ife ) is not so big, I could go for the kobo.
I couldn't try the paperwhite with my own hands because it's still not be sold in the shops here, you have to buy it online. You are surely more expert than me, which one would you suggest I should buy (if you know the paperwhite obviously)?.