OK if it helps you im going to go for the Kindle 3 this time on the fact that I own a prs-505 so im happy to keep that and the kindle wifi only is pretty much half price of the prs-650
I think for £200 Sony should have put a case and wifi with the 650 then maybe id have gone with that but ill get the kindle next month and wait an see what happens with the 4th gen
anyway good luck I know how it feels to be on the fence about which way to go (drives you nuts lol)