Kindle has the edge, but soon the device will matter less than the application, as this LA Times piece illustrates.

'Of course, iPad owners who read digital books tend to use Apple's iBooks app, which is linked to Apple's iBookstore, a direct rival of the Kindle. One in six digital book readers on iPad report using iBooks most, but Kindle follows closely with 31% who say they use it most often, according to the Cowan survey. Among hard-core readers who go through 25 books or more a year, 44% prefer using Kindle on the iPad, compared with 47% for iBooks — virtually a dead heat.'

FULL ARTICLE