Cote d'Azur

They are very diff. St Paul is small quiet, charming w/ great views. Nice is a big hustle bustle active beach city on train route.
Both are worth a visit for diff reasons.

nice is better as home base to visit towns along the railway. if you want to see hill towns you can take bus from nice.

We loved staying in St. Paul de Vence because of the incredible feel in the morning, looking down and across the mountains, toward the coast. If you go, even if it's a day trip from Nice, see if you can swing a meal at La Columbe d'Or. Amazing, amazing. Really a legendary spot. Also, just a mile further up the mountain is the great modern art collection, Fondation Maeght, which is in the most amazing setting you can imagine. Fabulous, fabulous sculpture outside, in the beautiful mountain setting.