Thanks for all the details. Yes, the Bamboo's tip deteriorates very fast. For my first one I didn't notice it at first, but after about 6 months it became almost unusable. So I ordered new tips, and the difference was amazing, that's when I started suspecting that it had started to deteriorate several months before. And now, after only a few weeks of use, I have a feeling that already it's not gliding as smoothly as it used to.
I just bought a new iPad last week, and since I now have 64 Gb instead of 16, I reinstalled a lot of apps I had trashed before, to try them again. For handwriting two things are important for me: the writing experience itself, and an uncluttered and efficient interface that lets me just write.
So far I have found two apps that fulfill these requirements: the Bamboo app, and Noteshelf. The Bamboo app might be the best of the two for the pure writing experience, because there is no need for a wrist guard, somehow the app can tell between your wrist and the stylus, so the writing is really natural. Noteshelf is the next best thing, because the wrist guard moves down automatically as you write. Noteshelf has a bit more functionalities and I like how the app looks, so that's the one I selected some time ago.