I could type forever, but I'll try being as brief as possible.
We got a great deal on the cruise about a month and a half before the sail date. We did the flight and hotel on our own. Checking in at Singapore was painless and was even a little earlier than what was listed on our tickets. The boat looked so little docked next to Costa Classica, but it was just fine for us. We were on the third deck but not too far in the back that it shook. We would walk the decks with our two year old and saw the difference the further back we walked. We had a great cabin steward (May) that cleaned our room amazingly well and paid attention to when we normally left for breakfast and dinner so we wouldn't come in while she was cleaning.
The breakfast buffet seemed to be pretty busy and we occasionally had a hard time finding a table for breakfast and lunch just before arriving at a port or just after a tour had come back. The restaurant never seemed really busy but served at a much slower pace. A problem for those dining with little ones. The food was quite good. I had read so many reviews complaining about food but we thought otherwise. Of course you'll come across a dish that you won't like, but for the most part we enjoyed every food experience we had on the ship. My kids were particularly excited to have a kids menu at the restaurant and ate their weight in ice cream during our two week cruise. We had the early sitting in the restaurant and had two great servers (Vassu and Suzan) that altered the table set-up for the kids after the first night. They also brought out their food ASAP to keep them busy.
We were slightly disappointed in the kids' room at first glance. It's smaller than the deck 6 bathroom, no joke. But, it doesn't seem to have too many kids at a given time in there. It is for 3-12 year olds (must be potty trained) and they have a teens club as well. It's usually opened 9am-noon, 3pm-5pm, 9-11:30pm. Some days were different, for example gala nights were different hours so they could eat with each other. For kids under three, they can go in but a parent must be with them at all times. Our two year old would go in and color for awhile and then move on. I hate to admit it, but they don't have much for the younger kids. Even my 3 year old spent her two weeks coloring. Regardless, she still loved going in there to play with the other kids. We did the Christmas cruise and there were about 25 kids registered. However, one of the kids' room employees mentioned the previous cruise only had 1. So, if you are planning on taking your kids, it will be hit or miss on playmates for your kids. One of the new features of the kids room, if you purchase an excursion through the cruise, the kids room will watch your kids for you at no extra cost. We ended up doing three excursions through the cruise and they would watch our 3 year old the entire time we were gone. She enjoyed playing and we enjoyed doing the excursions with one less kid. Also want to mention that my daughter loved the two employees in the kids room, Roberta and Yan.
We had fun on the deck 8 pool and hot tub. The hot tub wasn't that hot and was right next to a knee deep pool. It seemed like all the kids migrated to this pool. The pool on deck seven was very small and typically crowded. It was also very salty and bothered my kids' eyes. Seems like everyone mentions alcohol in their reviews, I'll keep mine simple. we bought a 10 drink pass for the kids. It made the virgin drinks really cheap and they enjoyed sharing a specialty drink. We really enjoyed going into the Flamenco bar at 5pm for happy hour and listen to the piano. We went the cheapest way and did the daily special drink during happy hour. 5euro for two or super size it for 5.50euro (plus surcharge of course) for two. It's cheaper than buying drinks in Japan, where we currently live. Overall, we enjoyed the cruise. The kids had fun, we had fun, and the staff were super friendly.
We'd do another Costa cruise hands down.