"but what concerns optics - are there noticable differences, and, mainly, advantages?"

Icono,

Not an Autocord, but I have a Yashicamat- and a Rollei 3.5F. I find that they are both excellent and deliver great image quality. Autocord are known for good lenses. The Rollei is special though. Corvettes and Porsches - two very fast cars that feel very different.

Your photos are beautiful.

Jeff