I've got an 8BitDo Pro2. I really like it, but I used to have problems connecting it over Bluetooth (wired would work perfectly fine.)
It just needed a firmware update. You'd probably be fine now (I've had my controller for a long time now, and rarely ever gave it an update), but if you experience connection problems with it, I'd try updating the firmware.
After doing that, my controller has worked like a champ ever since.