I got the H350 for my wife thinking that the two H505s I've had were so great that I couldn't go wrong, even though it was cheaper. I was wrong. She was telling me that she would answer the phone and there would be no sound and there was nothing you could do to talk to the other person. She kept having this problem periodically and I thought it was just her, so i traded her my 505 for it. I had the same problem. It would work for several calls, then I'd answer the phone and there would be no sound. It wouldn't let me transfer the sound to the phone, and if I turned it off, it would still beep when a call came in. The only cure was to turn the headset off, then shut the phone off, and on again. It was somehow taking over control of the phone to the point where i couldn't disconnect it. I sent it back to Motorola for a replacement, (their customer service is excellent by the way) but the replacement does exactly the same thing. Two different types of phones also, she has a Nokia and I have a Sony Ericsson. It's just not worth buying for the frustration you'll get from it. I've had two 505s and an 850, and the 505 was the best. There are issues with background noise interference, and I had trouble getting the voice dialing to work except when in a quiet environment, but the 500 series is an excellent and extreemely comfortable piece.