Ragusa, Noto or Modica Sicily?

Haven’t been to Ragusa, but have been to Noto once and stayed twice in Modica. Between those two, my recommendation is Modica all the way.

Modica is beautiful, especially the upper town, but the lower town also has the fantastic chocolate shop. There are lots of stairs to get between the upper and lower parts, unless you use the road.

We went to Noto because the Lonely Planet guidebook suggested there was an outstanding ice cream shop. We drove up into the town, and found an open parking spot, but a woman came out of her house and chewed us out for trying to park in front of her house. We found another parking space and found the ice cream place. It was OK, but not phenomenal. Same for Noto as a whole.

I’ve made two trips to Sicily and stayed in Modica both times. It’s definitely worth a visit.

We haven't been to Ragusa, but stayed in Noto several years ago. Thoroughly enjoyed the baroque architecture in Noto. We also took a day trip to Modica, which we also liked. If you go to Modica, stop by the Bonajuto chocolate shop..interesting, different tasting chocolate.

All three are similar in terms of architecture and "feel", but Noto is much smaller (has a flat main drag between two historical gates) and is only an hour away (as opposed to 1.5 to 2 hours for the other two by bus or train). It will take you less time to thoroughly tour Noto than the other two. I loved Ragusa, but it took all day to see the upper and lower towns while using public transport from Siracusa. Since you're going all the way to Vittoria (I assume by car), then you can easily stop at either Ragusa or Modica. They are both hilly and you can view Google photos online to see how similar in look they are. I picked Ragusa because it was chock full of old, historical churches, palazzos, and the like and the photos were very captivating.

We stayed in Ragusa but visited Modica. We went to Modica to visit the chocolate factory and saw the cathedral as well. I think Ragusa is prettier-at least Ragusa Ibla. We climbed all the steps to Superiore but really did not explore it.

But parking is easier in Modica which is no small thing.

We had planned to visit Noto as a day trip but ended up staying in Siracusa instead.

Frankly, I would visit which ever one is easiest for you logistically. It sounds like you only have half a day.

Whichever one you choose, you may want to start your exploring with a little train ride!
It seemed a bit touristy etc, but actually it's quite inexpensive (I think 5 euros), open air, and helps to orient you to the hilly towns. We stayed in Scicli, took the first one there, then made it a point to take the trolley in Modica and Ragusa. Both were fun and twisty windy, hilly. Afterwards we had a lovely cafe meal in each town square.
https://www.treninobarocco.com/en/