A few years ago, my wife and I both upgraded phones and purchased bluetooth headsets. She bought the 510, I bought something else. Hers worked nicely, mine looked good, but didn't work. Flaky, poor pairing, bad sound, uncomfortable...etc. Gave up on that one and bought a different one, also with nice styling. Same story...again and again. I've tried units from Jabra, Motorola, other Plantronics, and none came close to performing nearly as well as my wife's 510. So I finally gave in and got one of my own. It will likely be the last one I purchase. It just works. NO issues pairing. I don't even think about the operation anymore...I just turn it on. The sound is great...walking in wind, driving in the car, I have yet to get the complaint from those I'm talking to, which was all too frequent with every other unit I tried. I still don't particularly care for the styling of the unit. It's bulky and not very attractive, but the functionality more than makes up for that.Bottom line, not the best looking on the market, but it just works.