I’ve been a couple of times, it’s alright for a bit of a chill out if you avoid Budva (unless you want to party) I’d recommend somewhere on the coast north of Budva, near to Tivat. Swim in the sea, hire a boat to go to the blue caves, eat sea food, that sort of thing.
Kotor is worth a visit, it is slowly losing its charm to the cruise ships but it’s arguably more interesting than Dubrovnik, do the climb up to the citadel early in the morning for clear views and to avoid the heat (assuming you are going in the summer, it gets hot), has a bit of a cat problem.
Lovcen on top of the black mountain and Cetinje are a nice day out, and so is Skadar Lake if you like wildlife, birds etc, but the drive from Rijeka Crnojevića to the Lake visitor centre was pretty hairy, glad we were on the right and the drop was on the left.
Friends of ours have a nice place in Bigova, we’re working on getting the train from Belgrade to Bar in the summer, supposed to be one of the greatest train routes in the world.