I happen to have read both that book along with several on programming in cocoa (never done either professionally, I was just curious, so I claim no authority) and I thought that the systems (both what you can do with ironpython and wpf in general) turned out to be generally comparable in terms features, albeit grounded in differing philosophies and idioms. That said, what is the ideal to which WPF should aspire? If not Cocoa, then QT? Gtk?

I am curious mostly because I see a lot of this sort of nothing-new-under-the-sun critique of WPF, and while I have not worked with it in any great depth, what I've seen has been impressive enough to put doubt in my mind about such statements.