I don't have this bracket, but I do have the PMG bottom plate for a 1D3/1D4 (not the L bracket) and a coincidentally a bottom only plate from SunwayPhoto on my 5D3.
For the price the PMG is a well made, light weight and very form fitting bracket that fits the contours of the rounded 1D body perfectly.
It came with easily removable stops, as well as two allen wrenches, one for the stops, one for the main screw. The quality is very good.
Compared to RRS or Kirk? Well, it isn't in the same league. It will do exactly what those others do, and likely just as well, but the gloss black powder coat enamel is much less than the perfect anodizing you get from RRS, and looks like it will start to wear much sooner, however, after about 1 year mine is still wear free. So my gut could be wrong about that.
I have a Sunway plate on my 5D3 (again, not the "L")
I'd give it the same high marks as the Promedia for fit to body and usefulness. It too came packed with all allen wrenches required. It seems a little better built than the PMG, and has a more conventional matte black anodizing that still shows no signs of wear after about a year of use.
P.S., the guy that bought the one for 5D3 with grip was very unhappy;
http://www.amazon.com …ds=promediagear+l+bracket