I have 3 Sony's and I bought my mother a kindle keyboard.I have no experience with the kindle Touch.
The Sony's are much better for organising and finding books. No random hopping around of collection order, B is after A and before C.
The reading experience is much the same although if given a choice I would take the T1. Recognizes custom fonts and styles where the kindle does not seem to. More of an epub VS mobi thing. And of course most libraries have epub.
I don't care about Whispersync as I can generally find my place in a book in under 30 seconds, but can understand it's appeal. Perhaps if I am on a bus and want to read the book I was reading at home and it is not on that device, but 3G is not available where I live and the chances that I would connect though wifi hotspot long enough to actually whispersync anything are a bit slim.
Still I got the kindle for my mother who is 87 and lives 2000 miles away so I could get her books and have them directly sent or email them to her. She loves it, but last year I let her try my Sony 350 and now she wants a Sony. Oh well.