This is a marriage made in heaven. Among the most awesome lenses in Leica M's line up, the 50mm F1.4 Summilux is one of my all time favorites. Having used this lens for a few years now, I am convinced that its one of the best portrait lenses ever made...if not the best.
Using it on the amazing Sony A7 Series... Leica's optics comes and shines brilliantly. Awesomeness is an understatement for this combination of camera and lens. This is indeed my feeling, but perhaps you share a different view. I put it to test today and here are some samples. Feel free to leave comments.