My wife and I ride separate bikes and use the standard H-D CB to communicate. No VOX. In addition to the problems described by others who have attempted to use VOX, I am always afraid that I might say something that I don't want anyone else to hear.
Harley intercom can be installed without the CB, or rear speakers. Just the intercom. If using the Harley system, it uses the VOX and has adjustable VOX sensitivity as well as the volume for the intercom. But you do need the HK radio.
Does it come with a noise cancelling microphone or can you hear the wind noise / other noises through your speakers as well as through the helmet in general?
I'm not against always-on so long as it doesn't sound like I'm riding through an echo 24/7.
Look at the integrator it is vox operated. mine is always on... i turn it off but my wife taps me on the shoulder and i turn it up to talk... sounds like a pain in the *** but it's not bad... i can hear the music and the CB clearer with the INT volume down. There is a bit of wind noise with open face helmets , not so much with full face...I mainly wanted it for the CB so it may not be for you.