Me and the wife have jawbone IIs and love em. If you can get the fit right (first poster is dead on) they are great. If not, you will hate them.
Some days I forget I am wearing mine - at least until I get an email and it starts getting read to me. Still freaks me out a little
Per post #8, I think the jawbones turn off when you plug em in to charge too. Actually I don't know of any that doesn't.