Serenity Caldwell loves Adonit’s Jot Touch, but not the supported apps:
The result is that while I love working with the Jot Touch, I’m less thrilled about the way Jot Ready apps are integrating the Adonit SDK. Some apps implement only opacity—which I find nigh-useless unless I’m using a paintbrush or airbrush tool—and leave out brush sizing. Others have no way to customize or calibrate brush strokes, a deal-killer for artists who, for example, use more pressure in particular situations and would like to be able to alter the brush accordingly.
The Adonit Jot Touch is the first pressure-sensitive stylus available for the iPad. Sounds like the stylus itself is excellent but it’s going to take a while for iPad apps to implement good support for it.