I have used both C-bin and D-bin P7s and have ordered all from Photonfanatic. I have seen a small increase in brightness, and my last DSXOJ had a forward voltage of 3,5V. Thats just at the top of the DSXOI-bin... Generally speaking I have seen a lower forward voltage on all LEDs from Photonfanatic than on the ones from the HongKong-dealers.