I don't think the primary advantage of a Kindle (over the air purchases and stuff) works here in Canada, so the Sony looks more attractive to me.
The 505 is supposed to be good, the new 700 has a much glossier screen and lower contrast which defeats the whole point of an eBook reader.
The Kindle is also quite restricted as far as file formats are concerned, I don't think it supports PDF even. Whereas the Sony supports more file formats.
http://blog.wired.com/gadgets/2007/1...-kindle-v.html
So if I already own a book I can go find a digital copy in a PDF file "somewhere" on the net and read it without having to buy it again.
EDIT: I don't have one yet though.