thank you all for your points: they do read a lot of novels, and this is what I suspect they will read on the device (no pdfs then). So epubs would not be a problem on the small screen, as they could scale up - the problem might be only if they have a psychological resistance to this "small thing".
I like the idea of a 5'' screen because I suspect it is much less breakable (at least, my 360 has taken quite a battering, and a year on is still going very strong - my husband regularly keeps his in his jeans backpocket, I shiver every time I see it, but the good old 360 seems to be copying ok, a year on), and the cover of course is a big plus.
Billi, I don't think they'd have a chance to try them (still pretty new in Italy), and I only have about a month to sort this out, but won't be able to go there before and show my reader to them (my dad looked interested, my mum did not, but I think she'd use it if she had it - well, I hope).
Problem is, although they both speak English, I think they'd be annoyed if the language setting could not be switched to Italian, does anybody know if it is supported?