For the gen, there are no difference from looking at it & if you know where to look. Anyway, Rep only have 5001 (which some TD called them 5007). ZF v2 should be the best but once I see the YL v4, the movement plate is upgraded the same as ZF v2. Now the difference only on the dial and hands. I would say very close between these v2 and v4 now.
From my observations, ZF dial mostly have crooked 10 and 11 but YL doesn't have. The dial colour of ZF is closer to Gen compare to previous YL edition, I've not seen YL v4 dial yet so cannot confirm it had changed much.
Summary, if u like it. Buy the latest version either from ZF or YL depends on your budget and liking. Good luck and welcome to the IWC family.
Sent from my pigeon