Rory Marinich, with a great User Experience-oriented perspective on the complaints about the iPad’s (and iPhone’s) closed nature:
Does anybody remember what using a computer is like? I spent a week after reinstalling my operating system picking out the right tweaks and gizmos and gadgets to make things more manageable. Weblogs exist that do nothing but teach you how you can make your experience on a computer less shitty. On a closed system, you can’t do that.