In general, they stay was nice enough but spending an extra 10 minutes to do things like update the wifi code and username, put 2 sheets on the beds, put away the wet mop, and make sure everything was in order would have been helpful.
The good: Great location for exploring and walking to interesting sights. The apartment has excellent air conditioning and plenty of towels, and some lotion and toothpaste were provided. The kitchen is well equipped. Carmen was helpful by calling us an early morning cab when we checked out at 6am.
The not so good: No one was there when we showed up at the expected time. After a little wait, Carmen arrived, gave us keys and left immediately without showing us anything or giving us wifi info. The name and password were all wrong. I speak Spanish so there was no language barrier but she seemed to want to get away as fast as possible.
The building has ongoing construction so there was hammering and loud noises at times but otherwise it was quiet. You should like very firm beds if you stay here. The upstairs bed had only a fitted sheet and blanket but I found a top sheet in a closet. The apartment appears to have been recently remodeled to make 2 floors with EXTREMELY LOW CEILINGS. Upstairs, they are less than 6' or 2m. I am 5'8" (172.7cm) and I had to duck to walk to the bathroom. When I got up in the middle of the night to use the it, I forgot to duck on the way back to bed and hit my forehead really hard on the ceiling beam, leaving a bruise. The living room ceiling is also very low. I would not recommend staying here unless everyone in the group is under 170cm or under 5'6" There were no curtains or blinds for the windows. At night, there was a bright outdoor light shining in the window. I would also not recommend this apartment if you want warm water for showers. The showers look very nice but apparently, most Cartagena apartments in the old city do not have hot water and there is none in this apartment. Overall, I would not stay here again but it would be good for short people who don't mind cold showers.