Why Apple’s iBooks Numbers Are Meaningless
bits.blogs.nytimes.com
bits.blogs.nytimes.com
As a single data point, I've downloaded about 20 free books (I've read The Invisible Man and I'm halfway through Pinocchio). The overlap of free books on Kindle vs iBooks is pretty high (mostly all from Project Gutenberg).
I think the iBooks ability to download a free sample (usually first 30 pages) is the killer difference. I've downloaded a few samples when I first heard about a book, and every time I open iBooks they're there reminding me about a book I wanted to read, that I can pay for when I'm ready. Maybe the Kindle device has a better "shopping list" type feature, but all Kindle book purchases on iPad have to go through the browser.
I think iBooks is a better service, but the huge Kindle catalog will help Amazon. For a single book, the programs are similar enough that I'd just buy it from the cheaper store.
I bought the book from BN instead of Amazon because BN's book was $4 cheaper.
Kindle and BN also do free samples.
http://www.teleread.com/2009/06/14/the-kindle-chapter-previe...
They have one implementation feature that warms the cockles of my conversion-optimizing heart, right at the end: "Enjoyed the sample? [Buy Now] or [See details for this book in the Kindle Store]" Not only is it one click ordering, I'm 99% sure that they're A/B testing that call to action.)
My only gripe is that if you buy the book, it starts back on the first page, which is a pain because you're an arbitrary length in the story and getting back to where you were using Kindle navigation leaves something to be desired.