I have the Livescribe Echo pen
In theory, it's nice because I don't pay attention well so it's great to have a record so I can go back and listen.
In practice, I find that I rarely feel like I have the time to go back and listen again. It has to be super important to get me to do that.
This might just be me though. In general, I take a lot of notes and then don't refer back to them. I tend to have a separate pad of stickies where I write next actions, so they don't get buried in the notes and I can just throw them in an in-basket and process them.