I just received my Jawbone on Friday. I guess I was lucky to get my order in on-line before Jawbone ran out. I've had the Motorola 850, Motorola hs-700 (a and b versions), Plantronics 640, Jabra JX10, and Nokia bh-800 headsets. There are pluses and minuses to all of them, but I am very pleased with the Jawbone and I'm sticking with it for a while. Here's my take so far:

1. Noise filtering works as advertised. It's absolutely amazing. Much better than any other I've tried. People on the other end say it sounds like I'm speaking on my regular phone in a quiet room.
2. The sound coming through the earpiece is a bit tinny, but it doesn't bother me because the sound level and clarity are good. The Nokia hs-800 is probably the best in this category.
3. It is lighter than I expected. It took some playing around with different earpieces and ear hooks, but I finally found a comfortable fit. The Nokia hs-800 and Jabra JX10 had slightly better fits, though a little bending of the metal makes for a snug fit.
4. The connection quality is perfect. I don't hear any background hissing at all. It outperforms all of the others here. The Jabra JX10 was surprisingly poor.
5. The controls are easy to use. The noise filter is on by default with each call, which is fine with me because it works. The volume control is only in 1 direction, but again, I haven't found it to be much of an issue. Pressing the talk button once when it's on standby activates the voice dial feature of the phone. You have to hold the button down on the Nokia which is a total pain.

Overall, it's been the best one for me.