In what kind of device are you using the Duracells? I've noticed that mine seem to do great in my moderate-draw GPSs and have better run times than any other cells I've used. But they aren't at all good in my digital camera when compared to other NiMH cells.
It would be nice if a quick test of open-circuit voltage were a valid measure of the cell's state of charge but I don't think it's indicative of anything useful except to show that the cell isn't completely discharged.