This cruise was absolutely wonderful. The ship is one of the oldest and smallest in the fleet, and we were still constantly blown away by how big, luxurious, and clean everything was. We were not lacking in comfort at all, in any way. The food was out of this world, our cabin was perfectly sized, the beds were very comfortable, almost all the staff was friendly and helpful and the onboard entertainment was abundant and good quality. We were a bit concerned about getting seasick, but were not seasick at all the entire trip. It's so smooth, you can't even feel any motion most of the time!
We originally chose this cruise thinking it wouldn't matter that much what the condition of the ship would be like, because we mainly wanted to focus on the ports of call. That was honestly not the right frame of mind to have going into this, because you will spend A LOT of time on the ship, and it can really make or break your experience. But we honestly got very lucky and had a fantastic experience.
There were only two real downsides. One was that our itinerary got changed in the middle of the trip due to a storm (not Royal Caribbean's fault, obviously) and we had to make last minute plans for something to do in Athens instead of Mykonos, like was planned. Because of this, several activities we counted on didn't wind up happening. But in fact, at every point on the way, when something no longer was available, Royal Caribbean ensured that another opportunity presented itself, and none of them were lacking.
Beautiful city, definitely plan to have at least a day or two in Venice before or after the cruise.
I did an separate Game of Thrones tour from the one the cruise was offering. So much fun, so interesting, so personable with a small group. My mother, who I traveled with, did one of the cruise-sponsored boat tours and enjoyed it. Then we walked around the city a bit on our own, and really liked what we saw.
We decided to go to the Acropolis on our own. It was definitely a mistake, as we had to wait in multiple long lines under the hot sun to get inside, and also had to manage going a and coming from the boat to the city. Furthermore, one of the cruise excursions of the Acropolis would surely have provided us with a lot more context and information about the Acropolis than what we learned by just walking around on our own.
Having said that, we really enjoyed the Acropolis, and what we saw of Athens and Piraeus.