That's been my experience with BT as well... basically it's the "Swiss cheese model" where every BT implementation has problems, but you can sometimes find pair

That's been my experience with BT as well... basically it's the "Swiss cheese model" where every BT implementation has problems, but you can sometimes find pairs of devices which don't hit each others holes, and once they work, tend to keep working. So you keep trying different sets of devices, and then once you've found the right ones, cling to them like a drowning man to a rock :)