My much loved Kindle gave up the ghost this week so I would like to replace it with a new Paperwhite. I've looked on the John Lewis website where they have the 2013 edition listed as having 2GB internal memory. Since JL offers a 2 year guarantee, I was originally planning on buying it from there. But then I accidentally stumbled upon the Curry's website, where they have the Paperwhite listed as having a 4GB internal memory. Which one should I go with? I would like the latest one obviously but I really can't decide whether the 2 year guarantee from JL is worth sacrificing for the 4GB one