Only have time for one or the other. Which one would you choose? Not too stay overnight but driving from Noves.
I would head to Nimes. It has a more impressive colosseum plus the Maison Carree.
The only attraction that I think gives Arles an edge over Nimes is Arles' Museum of Antiquities, with its fascinating Roman barge.
My vote is for Arles a bit hilly which makes it lovely with the amphiter at the peak. I have been to both. Nimes is flat and much less to no ambiance., imo.
I have been to both and Arles has more to offer for me including the museum,Roman Arena,Classical Theater and Rhone River.
Mike
Tough choice - I liked them both a lot. Nimes's arena is almost totally intact, and had a fascinating audio tour, so that gives it the edge for me. But you can't go wrong with either one.
Where else are you going? There are lots of other places I would cut so that I could see both Nimes and Arles. For instance, for me both were far more worthwhile than either Avignon or Aix-en-Provence. I know everyone has different reactions, but you did ask for opinions and experiences, and those are mine.
The other places we would like to visit are Orange, Vaison-la-Romaine, Dentelles de Montmirail, and the Luberon area. The routes are described in RS Provence book, in the Cote du Rhône Driving Tour. We will be in Provence for only 5 days. Would also like to see the Camargue area if time.
Orange only needs as much time as it takes to see the Roman theatre, which is amazing; however, the rest of the town is a bit grungy, so no need to linger. I didn't have a car, so I didn't get to the other places on your list (they do sound nice - again, tough choices!).
I liked them both, but I'd go for Nimes.