What's the best Mac alternative to OneNote

Undoubtedly we've found that using Microsoft's OneNote to be a wonderfully natural companion to the wiimote project and our 3pi pen. The search is now on for a Mac version that gives Apple users the same interactivity as our Windows users.
We're wondering if we've found the answer in Circus Ponies Notebook 3. See http://www.circusponies.com/videotour . It can be downloaded for free at http://www.circusponies.com/ . This will give you a 30 day free trial. We're interested to hear from anyone who has used this product. On the face of it looks as though it will do everything that a teacher could want e.g turning your apple computer into a tablet albeit projected onto a screen, whiteboard or wall!