I bought one recently. I don't wear a helmet normally, but needed a new one for interstate travel. My ancient one was pretty ratty, even though it had been sitting in the basement for a couple of decades.
My buddy Bob decided to buy one too. We've tested them a couple of times and they seem to work pretty well. I'm actually surprised by how well they work. Another friend has a Sena 20 setup on his helmet and our Calvary helmets synced up with him no problem. All three helmets were connected via the intercom. My iPhone6 synced up no problem.
I haven't used it enough to get comfortable with the button sequences for changing modes or smothly answering the phone calls. I just can't make myself wear a helmet often enough. But, I think it does what it claims, can't swear to the intercom distance of 1/2 mile though. However, Bob dropped pretty far back one time and we could still communicate. Obviously the faster you're going the more wind noise is going to limit the ability to hear clearly.
One "issue" I've noted; it doesn't have a mute button. This means that I was listening to Bob's stereo speakers being picked up by his helmet microphone until I got sick of it and disconnected.
One other note; the charging port is on the outside of the helmet shell, under a rubber gromet on the button housing. I can see the buttons staying waterproof for a long time, and maybe the charging port will too. But with constantly removing the gromet to charge and that rubber drying in a couple of years, it seems the charging port should have been inside the helmet shell.
