Found a good video here showing the page turning difference:
http://www.youtube.com/watch?v=B8GBNR-MngQ
You can see the sony ereader goes inverse and then changes to the new page, while the iliad fades to white, then black then the page. I don't know if this is purely a software thing iRex has done, or whether it is a limitation of the 4 grey scale e-ink display used in the sony.
Heh just noticed it was posted on youtube by the above poster