I am just back last Sunday off Costa Fortuna. I have posted a review in the "Cruise Reviews" section of this site.
To answer some of your questions, personally, of the 3 cruiselines we have cruised with (Airtours Carousel, Thomson Spirit and Costa Fortuna) Costa wins by leaps and bounds.
I do appreciate though that Costa will not be for everybody as you are in the minority, being English spoken and you also have to bite your tongue quite a bit in how Europeans come across. We knew all this beforehand so were prepared.
I cannot really answer re all the entertainment as we only went to one show in the huge theatre and that was a classical concert!! There was some entertainment in the other lounges that we were at and everything is spoken in Italian first and then into English. It amazes me that so many people complain about the language problems. To us, that is all part of the fun, trying to understand and converse!!
Costa adds a 6 euros per person per day to your onboard account to cover tipping. You can modify this amount by going to the customer service desk.
Drinks we though were quite expensive. 7.50 for a gin and tonic, 4.75 for the beer my hubby liked to drink (Franziskanner) In addition to these prices were the 15% service charge. On the second day, we purchased 2 litres of gin for 23.99. We thought they may not let us take it away but they did. So now we could drink in our cabin. But we needed mixers!! We had a minbar which had cans but they were 2.50 (plus service charge) per can. Fortunately the next day we were at Katakolon, found a little shop where we purchased one dozen cans for 60 cents per can!! So now we had all we needed for pre dinner drinks in the cabin.
You can buy a wine package which is 5 bottles red, 1 sparkling white and 7 bottles water. The cost for this is about 105 euros. We did not bother with this There was plenty of iced water at the tables. If you wanted to buy a bottle of wine the cheapest was about 23 euros. Hubby purchased a carafe of house wine (1/2 litre) for 9 euros. Again these prices have service charge added. All the above prices quoted are euros.
We thoroughly enjoyed the cruise and would recommend Costa and we would definitely sail Costa again. Other pax are alot younger than previous cruises we have been on, also Costa attracts alot of families as I think they do alot of free child places. There were quite a few children onboard last week, the majority pre school age, although there were a few who I presume should have been at school. Personally I would not cruise Costa during the school Hols. However on saying that, I don't have kids so never take hols during school holidays.
Hope all this helps and any other questions please feel free to ask