A bit of both. I've bought gens and reps, but not of the same model. The last rep I've bought (a very good black / silver Carrera from Josh which keeps excellent time) was bought with the intention of seeing whether it would be too big for me to wear day to day - a 5 minute try-on in a dealer isn't really enough time to decide. The rep isn't, and it also keeps excellent time, so I'll probably hand on to it until it breaks, and then get a gen.
I've also bought a Sub rep, again just to see if I think it suits me - and I've decided it doesn't, so that's that. I still wear the rep from time to time if I think I may end up doing something that would damage a "proper" watch as it too keeps good time.
Just for the record, the gens are:
Heuer Carrera 2 register manual wind (60s)
Heuer Carrera 2 register automatic with date (70s)
Heuer Autavia 2 register automatic with date (80s)
For some reason I really like the pre-TAG Heuers, although other than the Carrera tachy chrono, nothing in the current line-up appeals to me at all - not even the re-editions due to the TAG element on the logo.