I had Cron 35 v3 until last month. While I can't compare side by side since the Cron is already gone, I don't see any size increase in actual use. 43mm filter size makes C-Biogon look bigger in pictures. And again, not needing hood makes C-B even smaller than Cron v3 because Hood was a must on that lens (at least my copy was) It's subjective and I have no intention of dissing Cron or blindly praising the C-B. In real use, I see size difference between the two are neglectable to me.
Tab vs focus ring is really a personal choice, and coming from Cron v3, I see no problem with C-B but I'm also used to other ring only lenses and lens that has both tab and ring like Nikkor-HC 50/2. C-B actually has a small bump on the ring that can act as tab with finger tip focusing. I find that quite useful, but I need more time with the lens to form my opinion.
It's just that I see no problem with this lens' ergonomics, but again, I'm used to smaller lenses like Elmar 50/3.5 (lever only), Elmar-M (ring only) and 28/3.5 (tiny lever only for focusing) so any of these lenses including C-B could use some getting used to if you are used to big lenses.
Edit:
And dfoo, I agree with you about 1/3 f stops. While digital and slide film folks probably appreciate it, I shoot b/w film only I don't even bother with 1/2 stops. My guess-meter is not that accurate anyway, and even when I use light-meter, I just round up to next larger aperture and deal with it in darkroom. But again, M8/M9/R-D1 users might like 1/3 stops.
