As I said, this is a headset that you can use for making cell phone calls. The microphone is integrated into the cord as part of an inline remote, which works with both Android and Apple iOS devices. The earphones charge via USB (the port is hidden in the right earphone) and offer only about 4.5 hours of listening time, which is pretty mediocre (again, it's hard to get a bigger battery in such a small unit). However, I did appreciate that there was an onscreen battery meter at the top of my iPhone's screen (the onscreen meter is tiny, but it's there).
A lot of people like to buy Bluetooth headphones for running and gym use. For lighter workouts, these would work, but they are less than ideal for more-active workouts. Plantronics reps told me that the BackBeat Go is for more casual use, for someone who's simply "on the go." The company's BackBeat 903+ Stereo Bluetooth Headset is still on the market, and that larger model is sweat-resistant and can be used for more-active workouts.
For better or worse, this is one of those products that seems to get mixed reviews from users. Some people really like it while others find fault with everything from the cord that links the earbuds (some people think it's too long, whereas others don't like the feel of it against their neck) to the size of the earbuds themselves (yes, they stick out of your ears more than typical earphones) to the so-so battery life. The buttons on the inline remote (volume up/down, answer/end call) are also a little small and may be difficult for some people to operate by feel. It's also worth noting that the on/off button, which is on the side of the inline remote, is truly tiny, and the minuscule LED in the right earphone that lights up when the headset is on -- or flashes when it's in pairing mode -- can be hard to see, especially in bright light.
Personally, I didn't find any of the flaws to be total deal killers, but it's easy to see that the product could be improved and that the next version of the BackBeat Go will be better and easier to recommend at this price point (about $80 online). I do hope Plantronics makes a BackBeat Go 2 or BackBeat Go+ (or whatever it chooses to call it) because this could be an excellent product with some refinements.