Done some more testing her, got hand on another u3 as well, total of 3 now.

1) Did work for a little while pretty well. then stopped functioning at all. Test different psu, cables, powered hubs etc. Cleaned up inside, still dead. Got a refund from Cryptocrane
2) The other one from Cryptocrane worked, but a bit slow. Faster now with the cgminer 4.8 build from Antminer, might be that one optimizes a bit better than i managed myself. Cleaned it up inside as well, no issues with just this alone now, nearly ever zombies. Directly connected to the pc, usb 2 port.
3) the new addition, reportedly unstable and zombie'ing. Cleaned it up inside, applied new paste etc. Working pretty well, but something wrong with usb recognition. I have to install the winusb driver again if i unplug it, even if back to the same port.

If i start cgminer with both connected, it fails. Starting cgminer, adding one, waiting till it runs, then adding the other, and they seem to be stable for quite a while. Not working with both of them on the same hub.
Zadig freezes if it believes driver install failed (even though it actually installs)