It is comfortable, stable on your ear, and very loud and clear sound quality.  There is only one other better Plantronics Bluetooth headset that is possessedly more advanced (655).  But I am extremely happy with this one, as it retails for about $50.  You can even buy aditional equipment and this headset can be used in your office or home with a regular land line as well.  Not only for cellular.  Awesome!