Today I received this email:

Hi Joeri

sorry, that I write you again. This morning, I had to return the M. It was really a joy to take pictures with it. I could test it in a lot of different situations, which I usually make pictures in. And now i´m fixed in, so i will get an M for my own ;-)…i think you knew this before!
But now is the question which lens I should pair with the body. I want an 28mm lens. For my test, I had the actual summicron 28mm/2.0 Asph and I love this lens. But a new one it´s way to expensive for me. So I see 2 options for me and I would like to ask you, what you think about it. 
The first option is to buy a used summicron 28mmm asph. I will get one for about €2.000,-. 
The alternative ist to go for a new or used 28mm elmarit asph. 
The Seller in the Leica Store considers, that a new elmarit has an improved image quality over a used summicron asph. 
I have to say, that the enormous sharpness and the non existence of image curvature of the lens I had for the test was a thing, I really fell in love with. 
What would you prefer?
Thank you in advance for the time I steal you!
Best Regards
Well, for me it’s a no-brainer. Even though I love my 28/2.8 for it’s incredible optics, light weight and small footprint, if I were to pick one lens and it had to be a 28, it’d be the Summilux, or the Summicron. The Summicron is pretty much as good as the Elmarit optically -or maybe just as good-, but it has two big advantages: it’s a full stop faster and it offers a lot more flexibility when it comes to depth of field. It is slightly bigger and heavier, but still very much acceptable. Get the Summicron. It’s a stellar lens.