This was my first foray into the BT department. I first had this paired to a Moto v551 then later to a RAZR v3 Silver and Black. The only shortcoming I can find is the method used to turn the unit on and off. There are times you think you have the headset turned off, but in reality you just redialed the last person called. The HS850 is a better designe here, but thats the only "one up" the 850 has on this headset. The volume and fitment of this 820 are much better than on the 850. I have only had 1 signal related issue and that was due to me being too far away from the phone. Overall a great buy!