I think a lot of the comments here could be attributed to the terrible Bluetooth software stacks that are around (Car head-decks, Android (all versions), Windows 8-10 default stacks).
I've got a brand new Plugable BT4 dongle that barely works in Win 10 because Broadcom haven't updated their suite so it relies on the default 10 drivers - you can't have a HFP and A2DP service running at the same time so a headset with speakers and mic won't work.
I've got a brand new Plugable BT4 dongle that barely works in Win 10 because Broadcom haven't updated their suite so it relies on the default 10 drivers - you can't have a HFP and A2DP service running at the same time so a headset with speakers and mic won't work.