This was my 8th Carnival cruise. I haven't been in a couple years.I took a Royal Caribbean and Norwegian for my last two cruises. I find myself coming back to Carnival because it is a "fun" ship.
I will start off to say the embarkation process was smooth. I stayed at a Comfort Suites in Miami Springs pre-cruise. I stayed because they had transport from the airport and to the cruise port. The hotel was nice, new and clean. Don't book the same transport company to take you home. KSA. They made us wait in the sun for well over an hour and then dropped us off on the wrong side of the terminal. I would recommend by hire the first shuttle you see when you get off the ship. They run you $10 per person.
The port experiences were great. We did the Key West bar crawl. Funny tour guy, Beau. Drinks were great and strong. In Cozumel we did the beach buggy snorkel. Be sure you have someone who is good at stick shift. In the description they say they have automatic available. They don't. The drive was an experience to be sure since I haven't driven stick in about 15 years. The fish were amazing and lunch was good. They took us to a hut for shopping and drinks. The people will bargain with you. Stick to your guns about what you want to pay. The sellers will come down to your price.
I stayed in Empress Aft. It was a window cabin. It was a good size for 2 people. Don't try to get more in there. You only have one electric plug. Bring an extender so two people can charge their phones.