Thanks a lot for the great comparison. These posts take a lot of time and effort, and you did an amazing job!
I personally have two main tells to spot a rep from a gen. The first is the cyclop. That's something you can notice immediately even from a distance (the AR and magnification). If you get to handle the watch, the operation of the bezel is the second instant give-away, as it's a lot smoother on the gen.
You state that you prefer the operation of the rep in terms of use of the GMT hand etc. I think the gen is actually nicer, as it lets you move the hour hand in hour increments quickly, which is great when you go from one timezone to the other. But I see your point. What is also interesting is the absence of quick-set for the date on the gen (i.e., you have to turn the hour hand forward or backwards till you reach the desired date).
Anyway, thanks again for a super post!