Focusing, focusing, focusing. You guys need to read up on how MA works. The micro adjustment you make heavily depends on the focus distance. That means of the million possible focus points in the universe, when you adjust the lens +2 and +3 for the distance X, it will still be out of focus for X+100 and X-250. You will sit there and spend hours pulling your hair out trying to get the perfect focus and you will think that you got it, then you will go out and take 10 pictures and see 9 of them will be out of focus.
I have spent so much time and money on so many Sigma lenses (because I actually used to think it was a waste of money to buy L lenses at first and how Sigma was "good enough"). I forgot to exact count, but I tried at least 4 50mm and 3 85mm Sigma lenses on my 5D III as well as 3 of the 30mm on my crop. After so many returns and so many shipping fees and twice sending my body in for calibration, I realized there is just no way to make this work.
You can make yourself believe that your MA is good enough, but I guarantee you that's simply because you are either not looking good enough or you are not using the lens in different settings in different apertures. Anyways, I finally gave up and sold all my Sigma lenses and moved to Canon's L glass and could not be happier. Now I buy a lens, put it on, and it works. Tack sharp focus in every focus distance.