I organized a group of friends (both American and Italian) for a week together without the need for being a host. We booked in April and wanted a fall cruise from Venice as that port would be convenient to all 10 of us.
Pre registration. The english Costa site was a nightmare. Some of us were not able to pre-register and had to wait until the e-docs were received so that we could fill them out manually and bring them with us.
Embarkation. Once you arrived at the terminal, you were given a number. There were two lines. One for Costa repeat customers, the other for the rest of us. You can imagine which moved faster. On the minus side, there were only four processing stations open when we came through. Costa had more staff hawking drink packages than they had processing the passengers. On the plus side, you did not have to stand in line until your number was called and there were ample seats available while you waited. On previous cruises, one card was issued that served as a charge card, embarkation card, and room key. Costa gives you a separate room opening card and you find your charge card on your bunk. You then have to validate the card at a kiosk. I had to go back several times before finding a functioning machine.
Cabin. Bunks were put together to make a double bed. Although requested at 2 PM, it took until after 9 PM for the steward to separate it to single bunks. Furniture was definitely dated. Several plumbing issues during the cruise while the maintenance staff did repairs. Steward did a good job of keeping the cabin clean and furnished for remainder of the cruise. Don't expect little extras like shampoo and mints.
Ports of call: Generally there was very little time available to spend on shore (typically 6 hours or less). Taking the Costa excursions lets you off the boat sooner and you can make the most use of your time ashore.
Dining. Costa did manage to assign all ten of us to one table. Even though we booked in April, we were told that there was no tables available for the second seating. That meant we had to fore go dinner in the dining room at ports such as Mykonos. On arrival there is one card in your stateroom that gives the seating assignment for dinner. There is nothing that says you must present the card when you go to the dining room. So, with a group of ten, we had five cards between us. We went separate ways and agreed to meet at the dining room at the appropriate hour. One member was turned away because she did have the card although she knew the time and table number. The Maitre D' directed her to the Reception Desk where she was given another card to gain admittance. Our table waiter was excellent. Too bad, the Maitre D' was so unhelpful. The buffet was quantity but not quality. I would suggest the Sinfonia dining Room for breakfast as you can get eggs to order and cappucino (not available elsewhere without cost.) Food quality was varied. Some nights it was good, others not. On Italian night, it was terrible. The native Italians at our table said there were ashamed to be associated with what was served. The lasagne was so salty that I only had one bite. At least the waiter allowed me to substitute some bread and cheese. On a positive note, there were always fresh baked rolls available.
Entertainment. Entertainment in the main theater was pretty good considering it was multilingual. There was a variety of things to do that would suit a variety of tastes.
General. Kat, the Costa staff member who did the English speaking orientations warned that the concept of lines (queues) was foreign to Italians. She said that it was just because they were hungry. It turns out they were also in a hurry for places anywhere a line formed. Generally, Costa had rules for how long the lounge chairs could be unattended, how many people could be in a hot tub, no children in the hot tubs,reserved seating for handicapped, etc. These were ignored by and large, and there was no action taken by staff to enforce them. Although, it was during the school year, there were children running rampant and unsupervised by their parents who seemed to be taking a vacation from parenting.
Bottom line. I have been on six cruises. This was the next to the worse cruise ever.