Here's my very brief, and slightly delayed impression of the trip.

The Ship - The interior decor of the ship was slightly tackier than we like, but apart from that, we were very happy with the room, food, common areas, etc. We requested a 2 person table at dinner and got it, which we were delighted with. All wait staff, bar staff and room staff were very helpful and friendly.

Getting off the boat, both for shore stops and at the end was very very easy. Do note that when they tell you that you have 5 hours at a stop, you don't as you have to be back on 30 minutes before the stated time. Many of the shore stops were very short anyway, so this was a bit annoying.

Naples
Naples is disgusting. Don't let anyone tell you that it's somehow, 'gritty and seething with life' and that by visiting it you see how Italy 'really lives'. I live in Europe and travel a lot, and I found absolutely nothing to recommend Naples. We didn't take a ship tour, just planned on doing a self guided walking tour. We had some time when we were done, but couldn't wait to get away from the smell of burning Vespa oil and back onto the ship. If you're on a boat stopping in Naples, either do the ship excursion or hire a guide to take you to Capri, etc. Our stop was too short to manage this on our own, so we decided to stay in town, which was a mistake.

Messina
We took the ship's tour here, as again, there was not enough time to go to Taormina on our own. It was a lovely ride and a very pleasant scenic little village and the tour guide was super.

Alexandria
We didn't want to make the day long trip to the pyramids, feeling they were worthy of a separate trip, so we took the short city tour. It was lovely, though the tour guide was not very knowledgeable at all and offered almost no interesting information. The bus was heavily guarded at every stop, which was a bit disconcerting. The last stop was at a dissapointingly tacky strip mall, with loads of time devoted to shopping. I'd suggest to book a tour with one of the firms advertised on Cruise Critic rather than taking your chances with the ship's tour here.

Limassol
Pretty but slightly dull resort town. We didn't plan an excursion here, just wandered around on our own. We found a restaurant, ate some grilled squid and had a bottle of wine and relaxed. The town caters to British tourists, so if you're looking for an English Breakfast, you can get one at any of about a dozen places in town.

Marmaris
We didn't do a tour here either, just wandered around on our own. The marketing for English tourists reaches a fever pitch here, so much so that we had a hard time finding a place that only served Kebabs. The town is pretty tacky, but the location is gorgeous, in a bay with tree covered hills surrounding it. Not much to see in town, though.

Santorini
This stop was not made due to an accident on the ship the previous night. This was simply another At Sea day.

Olympus
The English language tour we'd booked was canceled, as there were not enough English speakers registered. English speakers were BY FAR in the minority on the boat. We did the German language tour of Olympia, and were impressed with the tour guide.

So, overall, we were happy with the holiday though my husband found it hard to enjoy some of the stops as there was always the pressure to be back on the boat at a certain time. As long as your expectation of what you're going to actually see at each stop are low, I can recommend it. We were very happy with the amenities and service on the Costa ship.