Carlos bed, room, and shared apartment are super clean, well equipped, with personal touches that are above and beyond a typical place.
Carlos is a chill, gracious host. Easy to get along with. He works from home so keep that in mind if you plan to work form the apartment as well.
Wifi is solid.
Shower water pressure is just plain sad. This is common in CDMX.
Sharing a bathroom is as painless as it can be, but you can hear the bathroom clearly from the guest room.
Bed is comfy with plenty of blankets for cold nights.
Location is superb: you're in the NE corner of Roma Norte just off of Obregon.
The back courtyard is bigger and nicer than appears in the photos. I usually ate lunch out there, and parked a bike there often as well.
Overall for a shared spot, you'd be hard pressed to find better.