I don't yet own a D600 but I do own a D700 and a few weeks ago I ordered a Vello MB-D10 clone from B&H. The Vello looks just like my Nikon MB-D10 and functionally they work the same. The Vello is also much lighter making the camera + grip easier to carry. The only problem I've run into is with the EN-EL4 attached to the Vello BL-3 will only fit the Vello grip while the Nikon BL-3 fits perfectly in both. I'm confident enough from this experience that I'll buy the Vello grip when I get my D600.