Chirs: I'm trying again with most of the text of my attempt from the other day. So I got my BT300 and I think it's going to be OK. There are some quirks.I did go into Sound preferences and make the BT300 the default input/output deviceI typically use...

I tried to reply with a detailed post on my results (which were successful) but for some reason my message was disallowed. Great support experience so far 

Apparently, the BT300 adapter is required for reliable VOIP performance, in general. Here's what I was told by Plantronics support: The BT300 USB adapter is required, it provided the seamlessly audio bridge between the Headset and you OS X for use wi...

I've found with other tools, like Google Hangouts, that if I switch back and forth between audio output/input sources, that the headset will start to work. This technique didn't help with WebEx.