I can unreservedly recommend Restoran Santa Croce in Rovinj, where we ate two out of four nights on our recent stay there. Reservations are important, but both food, service and value are outstanding.
We also enjoyed a dinner at Bookeria, also featuring very personable service and good food. Seafood is king in this area and if you like fish you will eat very well.
We stayed at the Meleran, which is youthful in spirit (terrific young staff), but can require climbing stairs unless you specify a lower floor (we had one outside flight which was manageable; we’re 72 and 75). Transport by golf cart is offered between a somewhat distant private parking area (10 min walk) and breakfast is offered at a nearby cafe (decent although not memorable).
We thoroughly enjoyed our stay in Rovinj, although there’s not terribly much to do there except relax and enjoy the beautiful waterfront . We did drive to Pula one day to see the impressive Roman arena (parking was difficult even in late April), had a fabulous olive oil tasting at Chiavalon (HIGHLY recommend), and spent a day checking out nearby mountain villages (Motovun was extremely disappointing and I’d skip it - extremely steep to access by foot and little of interest in the Old Town once you reach it).