I've been using OneNote for quite some time now .. as well as using OneNote 2007 since beta2.
Took a look at EverNote's site and I can't say I'm impressed. I didn't really find anything I would like - except the fact that the basic version is free.
For instance, I don't like that they apparently save the stuff in a db .. with OneNote, you have everything within files - very easy to backup and transfer from one computer to another - also easy for syncing.
There are, of course, some interesting features - price, as I mentioned, is one. Then you have the encryption ability (perhaps OneNote has it .. have no idea - never needed sth like that ). And that's about that
Don't really listen to me .. I haven't exactly tried EverNote