I have used the Plantronics Voyager 510 BT headset for over a month and can say I am very pleased with the sound quality--both outgoing and incoming--it sounds like I'm right beside the person with whom I am talking. I often use it outdoors, in the car, and in the house and so far it performs quite well in all those areas.  I get the best results when I have my cell phone on me or am within  10 feet of my phone.  If I get out of range when NOT talking on it, it will beep to let me know and beep again a different tone when I re-enter the accepted range (approx. 30 feet). When I AM talking on it, the static will increase until I get back within that 10 feet or so.  Since I live in a poor reception area, I usually need to set my cell phone in an area where I can pick up a signal, and the Voyager 510 allows me answer away from the phone--at least until I can get to closer range for best reception.