I'm still deciding if I'll keep my Kindle DX. Today, while reading a sample book, I found a surprising new behavior. I very much like that most of the Kindle-format books have free samples available. While this isn't the equivalent of being able to thumb through a real book, at least it does allow you to get a feel for the work before you purchase it.
When you reach the end of the sample, there's a link to buy the book. My discovery is that when you click this link you instantly purchase this book, and just seconds later it's on your device.
Personally, I was expecting a confirmation step before the purchase was completed. But no. One click and your credit card is charged. Worse yet, there's no indication of how much the book costs. I supposed you're expected to remember how much it was when you requested the sample. I certainly did not, which only increased the anxiety I felt about this surprise purchase.
Fortunately, the screen that appears when you instantly buy the book has a link that allows you to un-buy it right away. This also works without confirmation, and the book is removed almost instantly, along with a message that your credit card has been refunded. Sure enough, when I checked my email later, I had two invoices from Amazon, one each for the purchase and refund.
So in the end, all was OK, but I found the lack of confirmation to be a bit rude, as well as the language around the refund where you have to click a link that says you bought the book "accidentally." That puts the blame on the customer, instead of on the device's interaction design, where it belongs.
See also Kindle DX: First Impressions.