Great sound, and noise reduction. Electronics, the best!BUT, the mechanical/material design is bad. So, how good is a device that sounds great, but it will break in less than a year ando so you won't be able to use it?Thus, the recommendation is only for those that can be careful enough so that the device will last much longer than what I did. I'll explain.I am an Electrical Engineer. I only implant the device in my ear when the phone rings (I want to minimize the RF exposure as much as possible, even though just by having the earpiece instead of the phone itself I have reduced it considerably). So, when not in use, I have the earpiece in my front pocket, sometimes just the main piece snugged enough but the metal ring outside the pocket, so I can retrieve it easier or faster. Well, the unit comes with 4 of these metal rings (goes around your earlobe); in one year, I broke off all of them near the base of the earpiece (where the metal ring is inserted). On the third metal ring, the base of the earpiece itself broke off, so I had to GLUE it so it would stay in place. Then, the little soft plastic piece that attaches to the earpiece and it actually goes inside your ear canal broke off as well. So, i had to glue that as well. Then, finally the fourth matal ring broke off at its base, and so now i have to hold the piece in my ear holding it in place by pressing with one finger, sometimes it sticks enough so that I don't have to and can actually drive with two hands (it defeats the purpose doesn't it).TOO MUCH! The mechanical design is faulty. They used a relatively heavier metal piece and married it to a flimsy plastic base. It simply doesn't make any sense.I'd hope they fix this problem on their second design the Jawbone II.