I can't explain the price difference, perhaps because of the lower quantities. But my OpenRun Pro has a specific charging plug. My wife's Pro 2 Mini has a USB-C port.
I used it several times for calls and asked the callers about the quality (cause I was worried that it‘s not that goid). All of them said my voice sounds very clear, and no disturbing noises at all.
Seems to be misinformation. Since the sound is transmitted to the bones, ANC is not possible at all. When I bought them, this wasn't even in the specifications.
How exactly do you mean? Openrun Pro is just a Bluetooth headset without its own memory. The hardware button supports. Play/Pause/Next/Prev nothing more