If you won't use it on a Leica, find out if you can collapse the lens into the camera body before buying one.
Even if it's a Leica M5.
Otherwise... it's a nice choice. I have one that came with noticeable cleaning marks (a problem with these lenses is their soft coating). However, despite this small defect, it works well and has a nice sharpness, like most of its contemporaries. In other words, it's not piercingly sharp all around, but does have a nice sharpness on the subject it focuses.
In addition to the cleaning marks, many of these lenses will benefit from a CLA. Mine came apparently well, but with time, the stops in the aperture ring started feeling odd... they got stuck at the wide openings. I sent it then to Sherry Krauter, and it returned a completely different lens, with nice stops and smooth focusing.
You are right in thinking about this lens if you want the Leica nameplate and aren't concern with all-around sharpness at wide openings. Just be aware that it'll need service, unless the seller can prove the lens was CLAed before you purchased it. At least, five years before... 🙂
Have fun shopping!