You can see for yourself the page-turning speed or lack thereof. Mobility Site’s accompanying post is here.
Related: My Nook tryout at the local B&N: A sluggish e-reader with confusing naviation, by Jean Kaplansky, and David Pogue savages the Nook in the New York Times: ‘A mess,’ by Paul Biba.
Have you seen this 25-minute video walkthrough of the Nook? He likes it, but aggh! it’s painfully slow.
http://blogs.zdnet.com/mobile-gadgeteer/?p=2232
On the other hand, turning pages and clicking to any page in the book are both instantaneous when I read on my netbook PC with Mobipocket Reader.