The shore excursions are all very good, but you have to make sure you are in an English spoken tour beforehand.
Food is acceptable. Dinner serving size are smaller but is just perfect for me. The buffet is crowded and the self-serving coffee and juice machines don't work sometimes.
But what I really want to compliment Costa is their great customer care to those of us who happened to be stuck in Genoa, Italy when most of the European airports shut down due to Iceland's volcano ash problem. For those who booked their air through Costa, Costa put us at the 4-star Bristol Palace Hotel which covers full breakfast daily, and assigned us to dine at a great local restaurant for lunch and dinner. As the airports gradually opened up, people got re-booked to go home. We ended up to stay at Genoa for 6 extra nights and we do appreciate what Costa has done for us. A+ to Costa's customer care!