Very interesting study and article on iPad app usability http://www.useit.com/alertbox/ipad.html A lot of those things are true (especially the inconsistency between apps). I hope that more app designers read what he has to say here, or at least what will happen is that the apps that take these things to heart will get better reviews and sell better than apps that don't. However, this shows an interesting difference between Apple's approach and other computer companies. Other computer companies would have run it through all of those usability tests and killed it because of those (or pushed out availability until 2020). The end result being that they lose sight of the forest for the trees. 3.3 million people so far are willing to put up with inconsistencies in the trees because they love the forest as a whole... Apple gets that.