I went and had a look at a unit at Borders in Oxford Street yesterday and was very impressed with the screen. Compared to the Sony PRS 505 I have I couldn't see any difference in the contrast and shade of grey in the background.
The extra space on the screen makes a huge difference! The fact the fonts can be bigger without compromising the amount oftext displayed on a line makes everything far more readable. I couldn't see much a difference in the speed taken to change pages either but thats never really bothered me on the Sony Reader. I also couldn't detect much in the way of ghosting but again thats never bothered me on the Sony and seems to get worse over time anyway.
I was sorely tempted to buy one there and then as I managed to break the screen on my 505 at the weekend by dropping a beer bottle on it.
The startup time and casing were very poor compared to the Sony though.