Avignon or Aix-en-provence

https://search.ricksteves.com/?button=&page=1&query=Avignon+or+Aix-en-provence&utf8=%E2%9C%93

Aix--hands down, but not for your reasons. It is a much nicer, pleasant town, with trees, cafés, fountains, shopping. It's also an international university town. It has more to offer for your five evenings strolling. There are some trains and buses; see rome2rio.com for transportation info for both towns.

Aside from the Pope's Palace and the theater festival in summer, Avignon is grittier. It's generally less pleasant for strolling. However, it is an important transportation hub which is convenient.

I base this on visits, property search, and conversations with residents. And one of my sons went to the university in Aix, while we lived 20 minutes away.

Avignon would be more convenient. There are more direct train options from Avignon with shorter routes than from Aix-en-Provence.

I’d listen to Bets, having lived in France for decades, she is our France authority (and a gem) on this forum.

I was in Avignon in Sept of 2019 and was not impressed.

I stayed in Avignon and only day-tripped to Aix (from Marseille). I thoroughly enjoyed walking around Avignon and am always puzzled when others report not having liked it. Perhaps my expectations are lower! But it's not just a matter of which town you're most likely to love the absolute most; you want to take day-trips.

Truly, what you need to do is read a good guidebook to southern France (I understand Rick's regional book is a lot more complete than the broader guide to France) and make a list of your A list and B list destinations. See how they fit with basing in Avignon or Aix. If unsure, come back here with your lists and ask. Aix is definitely more convenient for trips to Cassis and Marseille. The list of places often mentioned on this forum for which Avignon is a more convenient base is quite long (beginning with Arles, Nimes, L'Isle-sur-la-Sorgue, and Saint-Remy) so I really think you need to know where you want to go before you choose a place to stay.

Even from Avignon it can be difficult (or even impossible) to get to some of the tiniest popular Provencal destinations without a car. I regret not having researched options for one-day bus tours. One of those could have allowed me to see a few places like Roussillon that I didn't manage to get to.

Edited to add: I'm pretty sure Rick discusses choosing between Avignon and Arles in his "France" guidebook. I don't remember his including Aix in that discussion. I would argue that's because Aix is just not as convenient for what the typical American tourist wants to see in that part of France. There's no need to go along with what I say or Rick says. For one thing, your interests may not be typical (mine certainly are not). I urge you to base your decision on your own interests.

Without a car, you should only consider Avignon. Avignon is the transportation hub of western Provence. While I like Aix-en-Provence, it is farther away, somewhat isolated, and not as easy to reach, by public transportation, many of the popular tourist destinations of Provence.

From Avignon, it is very easy to travel to Nîmes, Uzès, Pont du Gard, les Alpilles, Arles, les Baux de Provence, St Rémy, Ile sur Sorgue, and you can even take the train to the beach at le Grau du Roi.

Just to see the bridge, le Pont d´Avignon, is worth the trip; particularly if you already know the song.

Aix-en-Provence is on my "next time" list, but my husband and I loved everything about Avignon when we were there in 2014 or 2015 (details fade). Avignon, IMHO, is like Saint-Malo, Strasbourg, and many other small cities in that it is a really nice place "to be" but without any blockbuster sites. We didn't take any day trips via train travel. Instead, we took a couple of small group tours that we booked with Provence Panorama. Both of our guides were great, and the customer service prior to our trips was outstanding.

http://www.provence-panorama.com/en/tours-reguliers.html

That's very kind Susan; note that I said not for the reasons they stated.
Aix is nicer town but Avignon is the transportation hub. And we don't know where the OP wants to day trip. Rome2rio will be a help.
I realize that my assessment may not fit the OP's needs.

One of the prevailing reasons we stayed at Aix, without car, was its a 30-45 minute bus to the airport to fly out of MARS at the end of our trip . And Flex Bus changed things up as to the cities you could day visit.

I stayed in Avignon for 5 days and it was super convenient for day trips. The city is fine, but I was really looking for a base.

Another vote for Avignon, especially without a car! Aix is less centrally-located and from Avignon we easily did day trips to everywhere listed by previous posters. If you stay in the old part of town, it is an easy walk to everything to see -- the Palais, cathedral, bridge, and just wandering. I didn't find it "gritty" at all, but Marseille, ah. If you're looking for gritty, try that! To get other views, you might want to just google "which is better, Avignon or Aix-en-Provence". There's plenty out there.

I was not fond of Avignon, but it is a transportation center, for both buses and trains. As others have suggested, you should check the connections from Aix. If you can get from Aix to where you want to go, I would stay there.

Our experience is limited but we preferred Aix over Avignon, and Arles over both. Avignon had historical sights that interested us, but we thought Aix was more attractive for strolling around. Arles combined the best of both worlds, and we stayed several nights and really enjoyed it. We did pick up a car later during our visit but used the train for other destinations, traveling sometime to Avignon for the connection. Just my two centimes. Safe travels. .

I haven’t been to either but am commenting because I really struggled with this same decision. I had Saint Remy and L'Isle-sur-la-Sorgue on the list for a while but removed them since Saint Remy doesn’t have a train station and L'Isle-sur-la-Sorgue was on the small side for us.

Both sound amazing but we decided on Aix because it sounds like it combines the best of both a city and village. Bustling and quaint at the same time. What Bets says about it is what we are looking for. Many restaurants and cafes, a walkable old town, book stores, daily markets, pubs, shopping, Vendôme Pavilion and its French Gardens, nearby parks, and lots of art galleries and museums:

Atelier de Cézanne
Hôtel de Gallifet
Musée Granet
Hotel de Caumont

We will take the train to Avignon, maybe Arles, Lyon and Marseille. We will take the bus to Cassis and rent a car to drive into the Luberon and Saint Remy. (Planning on a month in September)

We want to sink into the culture of a town versus sightsee a lot. This is a trip I researched with help from this group and planned for 2020 then cancelled. It is back on the books for 2021. Fingers crossed.

I’m not sure it’s the right base for a true sightseeing base by train and bus, which perhaps is more what you are looking for.

I’ll have lots more opinions after I make my trip ;-)

Keep us posted! Bonne journee!