Thank you for your quick and useful replies, guys.
Nine Inch devices, specially Pocketbook, are so expensive. But paying for something that you can't use (I mean buying a 6" device and finding out that it has no use for you), is more expensive!
As you say, 6" devices won't work for me.
I wonder, why Pocketbook does not reduce its prices while Kindle and Nook are getting very cheap.