I just received my EOS-M to EF lens adaptor in mail this week. I order one from China for only 15 quids.
Is working fine with Canon’s lenses, but a bit slow. I prefer to switch on “manual” mode and handle the focus myself.
Today the day was not too bad so I thought to give it a try using Leica R 50 mm F2 Summicron lens. Is actually not too bad! Of course I prefer this lend on a Full Frame, but is not too bad on a crop sensor either.