No love for BB, but I don't care since I have never used One Note, when it first came out it was an add on to Office and I didn't see the point, now it is in the latest version, but I have already gone down the Evernote path, which integrates well with Office and you can bring in so many attachments, in addition to it working across all platforms + the Playbook and IPad!!
I never saw the point of any "note" apps. I've never used One Note on my PC, and I never used any note apps on my Blackberry. I've always deleted Notepad and Tasks, since I didn't use them, and the Blackberry lacks sufficient memory.
I have been using Evernote for years. As Dave says its cross platform, reliable and more than enough for my needs even in its free app. Since I gave up on Outlook altogether (I rejoice the day) I have no interest in OneNote. But then, there are many that use it and swear by it.Different strokes for different folks, right?