I haven't used the Biogon or the Nokton, but have some experience with the Cron ASPH--and wasn't overwhelmed by it. I loved the size and ergonomics, but its images didn't have the character I was looking for. I found the character I wanted with the Lux 35 asph v1, and if I didn't have the money for that lens, I could have pondered the Lux 35 non-asph or the Cron 35 v4. I am a big proponent of making do with fewer lenses and, thus, would never want more than one lens at one focal length. (In fact, I have four lenses, but will get down to 2-3 at some point ... as soon as I get some time to list some items.)