OK, I'm not at all familiar with Nikon. But all the Leica lenses I've used have been very different from each other, largely depending on when they were made. Older Leitz lenses are soft and low contrast, nothing like my 60s Summicron, and the newer stuff is different again. Of the Voigtlander lenses I've used, the two wides (21 and 28) are high contrast and have smooth bokeh, the normals (35 and 50) much lower contrast and a bit ugly in OOF areas. I have three Zeiss lenses for the Blad, a wide 50, a normal 80, and a portrait 150, and they are all pretty different too, despite being of similar vintage (the wide is older, the other two about the same age), largely down to them all being very different designs, I suspect. Etc etc etc. I think all I'm saying is I'm not sure worrying about a manufacturer's signature is very worthwhile, much better to concentrate on finding equipment that best does the job you're trying to do, whether that's a specific lens for a specific task, or a format, or whatever.