A few people have commented about Yojimbo, including Brent, who gives it a place in his dock. His post has some good points in the comments thread. I've already paid for VoodooPad, and put a lot of my brain in there, so I'm not moving my notes anywhere soon. This is a good point to note if you're thinking of wading into the note-taking app market - if I can't move my data into your app, it's unlikely that I"m going to bother using it.
It's nice to see a real app shipped using Core Data - although the data model appears to be pretty simple. I wonder if they hit any snags developing it? I'd be interested to hear what kind of effort they put into it.
I have a couple of quick nits to pick, in case anyone cares: If you have a three-pane interface, the detail pane has to scroll when I hit the space bar. Especially if it displays web content. Let me say that more clearly: If you display web content, use different key shortcuts than Safari at your own risk.
There's a useful info inspector for the items, but Cmd-i doesn't bring it up - it is still trying to italicize something, even if I'm not selecting text. An issue of fit-and-finish I was surprised to see in a BareBones app.
Finally, it's simple and elegant - it gets the important things right, but I don't know if it's really solving a problem that many people have - casual users can store passwords and bookmarks already, and serious researchers have more powerful tools. Maybe the biggest missed opportunity is that a having a single place for all of this data would be a great start towards making it available to other programs, which I think is where the next big leap in computing experience is - think a combination of the iLife media browsers and bookmark/note taking apps, along with a bit of Onlife. That's what I think the future tastes like...