I went from MK2 to MK1 172. I had both cars about the same amount of time (10 months for each) and did the same mileage in both (12k in each). My MK1 172 was undoubtedly faster than my MK2 172, but I think my mk2 was a bit of a dud in the performance stakes.
I have to say though, I always much preferred the mk2 interior and toys, and to be honest, the MK2 handled better. I put some MK2 172 springs on the MK1 not long before I sold it which improved matters, but the MK2 just felt more planted and was less prone to understeer when really pushing it.
However, I hardly ever see MK1 172s around. Definitely the rarer car. Oh yeah, my MK2 rattled a bit, but my MK1 was a living nightmare. The whole rear passenger plastic panel detached itself and the whole interior rattled, banged, clonked and squeaked like a feckin b*****d. It was really doing my head in by the time it went. Its a tribute to Renaults piss poor build quality that an MG-Rover seems like a Rolls Royce in comparison.