+1 to infinity and beyond. In the end, it's about your aesthetic preferences and vision. Many photographers value the older lenses for how they render. Many places to learn about them. Here's a very good one.
The Leica M Lenses Forum is dedicated to everything around the Leica M lenses like Summilux, Summicron and Noctilux
www.l-camera-forum.com
I have shot (monochrome only) with an uncoated 1945 collapsible Elmar, a mid-1950s collapsible Summicron, modern Summicrons, and more-or-less modern Color-Skopars.
They are all rather different.
The uncoated Elmar does lovely and ethereal things with light sources and specular highlights.
The 1950s era 'Crons have a kind of low contrast look, albeit being very sharp, that I don't much care for. It's not that it's bad, it just that - to my eye - the images look flat and lack the "pop" that makes an image sing.
That's why I switched to Color-Skopars for my Barnack body. These are an excellent value and razor sharp. The 21mm f/4 LTM Color-Skopar approaches clinical levels of sharpness and rendering reminiscent of some the best Zeiss optics of yore.
My M lenses are all from 1970-2000. They are sharp corner to corner, contrasty and manage to do this without giving that clinical look. (I would imagine that the modern APOs are probably muchso, though.)
Though I've shot almost no color with any of these, my general experience has been that Japanes optics tend to render warmer while the German glass gives you cooler color rendition.