Thanks guys - I do give priority to wifi (although I do believe it should be off anyway, since I have ethernet plugged in), but I didn't know about the shared antenna. I have a very early unit, so that might be the issue.
I can't imagine to still have faulty controllers, because I got 2 for replacement already - I'm assuming these are with new firmware.

Did anybody try to use an external BT dongle? That would be a cheap fix, but of course it relies on the OUYA actually using the new bluetooth device.