I expect
Amazon tablets would sell for the same reasons Kindles sell -- their firmware would make buying content from
Amazon super easy, with great customer support and the ability to take your content to other devices if you choose. That's why I buy Kindle books nearly exclusively, even though there are plenty of other options. If I choose to switch hardware, I won't have to abandon my content, as I would with iBooks, for instance.
Amazon also has lots to leverage with a host of services and products. It has a credit card, bonus points,
Amazon Prime and other buying programs that it could use to help make its hardware and content even more attractive, for instance. The key difference between a company like Apple and
Amazon IMO, is its leadership. The companies both have visionary leaders in Jobs and Bezos, but Bezos's leadership seems much more open and embracing of what customers want. Bezos showed with Kindle, for instance, that
Amazon will admit mistakes and change services to better serve customers. I have great respect for what Jobs has done, and Apple certainly has lots of satisfied customers, but Apple customers have to do things as Apple decrees.
What I'd expect from an
Amazon tablet is essentially a more usable Android tablet than any other competitor could produce, with the whole package -- hardware, firmware, content and support. I don't think
Amazon would bothering producing a tablet unless it could deliver a great customer experience.