XPages are a huge divergence from classic Notes development. Aside from a few token UI controls such as View Panels and some support for Domino data on the back end, they may as well be completely unrelated to Notes.
Now, while IBM didn't take many strides to make the transition from old-style to new-style development easy, they DID make sure to keep the most important part of the Notes experience intact: horrifyingly frustrating bugs! Case in point:
All I wanted to do was delete the attribute value, but every time I did, the XML editor decided to eat a couple extra lines of code. The "select all" effect you see is from hitting ctrl-Z, which is supposed to only select the text that was un-deleted, but, since the editor has no idea what's going on, it throws up its hands and selects all kinds of crap.
Between this kind of thing and all the random crashes, it's comforting to know it's still the same level of Lotus quality we've come to expect.