We did a combination of both Ags, we are not seasoned travellers so did a few of the excursions, but it would be expensive to do them on every stop. It was only a few euros to catch the train to Monte Carlo so we did that, or it would have been similar to go to Nice. We took a coach only excursion to Rome as the tours seemed expensive, then we caught one of the sight seeing open buses around that you pay once then get on and off as you please. There are usually local trains or taxis close to where you dock.
We werent sure whether we would enjoy it or not, but it was a great experience, the ship would dock early morning and we would have the day ashore, back early evening for dinner and the show or disco and wake up next day somewhere new.
There was one formal dinner and if you dont want to eat in the restaurant , there was an excellent buffet, food was available 24 hours a day, so its not a holiday for dieting!
I would say if you fancy it , go for it, we will be doing another when funds allow!