Get Leica M lenses at B&H Photo.
In 2013 from April through August, I reported extensively on flare with the Leica 50mm f/2 APO Summicron-M last year, using two samples from the initial production runs, both of which had troublesome flare issues unworthy of a super premium lens.
In late summer 2013, Leica acknowledged the issues and took steps to address the flare issue.
Returning my lens in early September 2013, I received a replacement in late November 2013.
Now I evaluate the improved and updated lens:
There is more evaluation to do, but the revised lens certainly seems improved over the original.