I use a Plantronics 510 and it is excellent. Most people tell me I sound better on the headset than the handset. It has three different ear pieces so you can find which one fits you best. Has seperate volume for the headset so it can get quite loud.... I too am interested in the Jawbone. I saw a demonstration....and it looked very impressive. It's ugly tho.....LOL
I have the Blue Parrott and had the Jawbone, I just gave the Jawbone to a friend that does not drive any loud equipment. I just ordered another Blue Parrott to keep in another vehicle.