Having problem in very cold weather (-20C) with the 501, I bought this head as a replacement. The price in Canada are very low and the plate are also realy cheaper than the wimberly one (half). Wow! the action are realy smoother than the video head and it is a one finger operation. The horizontal panning are not smooth as the vertical one, at least on my copy and also compared to the wimberley (in horizontal). with my 400mm f5.6 lens and a heavier body like the 1D or maybe a XXD with a grip, I feel it balance better without the L shape accessory, so in that case the "light "version are enough.