Well, I just got out my gen 1680 to beat on for a while since I want to keep the 1665 and 5514 I built nice . Not sure what that says about me, but the frankens mean more. The flip side is a little wear and tear usually helps the frankens look the part.
They all have gen bracelets and clasps (which take most of the damage), movements, bezels, dials (5514 is "pre-Comex" so a standard 5513 dial), etc. so this makes the decision easier. Other than the mid-case, any damage is being done to a gen part.
Over time, the reps I most enjoy have become copies of gens I like. I have some great PAM reps (real dials and hands, Rolli dials, etc.) but I guess I never really liked the gen design so I rarely wear them. The recent IWC Portos on the other hand get lots of wear. These are also great reps since I would be really disappointed to pay 8K for the Porto automatic having experienced "the watch" for a while.