At some point I had 4 of them, now only 3 remain in the collection.
They're warm to neutral lenses that sharpen up quite nicely at f/5.6. they were designed as a cheaper alternative to the Hektor 5cm.
Their front element is pretty soft and scratches easily. People pay top dollar for clean samples, but I get nice results with marked ones all the same. The summitar, and lately the Hektor 5cm f/2.5 get to spend a bit more time on my Leica bodies.
Leica I, Summar 5cm f/2, Agfa/Rollei Superpan 200, Y2 filter.
I can probably squeeze a bit more out of the negatives these days
Leica IIIb, Summar 5cm f/2, Fomapan 100