Carlos and Gabriela are wonderful hosts. They are responsive to requests but also leave you alone to go about your business. Both are lovely and friendly people, and Carlos is fluent in English. I stayed in their cozy renovated garage studio for 3 weeks while I was in an intensive language course nearby. It was the perfect place to stay! The studio had everything I needed - a comfy bed, big desk, kitchenette with frig, micro, water filter, tea kettle, hot plate and the basic items (plates, silverware, pan, etc).
Both the supermarket and the metro are ~10 min walk, the language school (International House Mexico) is ~5 min walk, Parque Mexico ~10 min, lots of restaurants within easy walking distance. A perfect location in beautiful and peaceful Condesa. However, it is a ~30+ minute metro ride to the Zocalo (downtown) or via Uber (even longer with traffic). So think about what neighborhood you want to call "home." CDMX is an enormous city with truly hideous traffic. The metro avoids the traffic but it doesn't go everywhere and can be delayed.
The studio is not overly spacious. It's great for one person but I think it might feel a bit crowded if there were a couple and you hung out in the studio a lot. There are 3 places to sit: on the bed, or the chair at the desk, or a stool. Also, the bathroom is small and rather short since it's built underneath the upstairs staircase. For me (5'4") it was no problem. It has all you need but in a compact space. The doorway into the bathroom is ~5'6" tall, so tall folks would need to duck to enter. The shower is part of the bathroom, and you need to squeegy the tile floor to help the water get to the drain (there is a shower curtain of course, so your things don't get wet, just the floor). Not a big deal, takes less than 2 minutes when the shower is done. Being a garage, it's right on the street. Mostly the street is quiet and peaceful at night but on occasion there is noise during the night - people or cars. I slept with earplugs and eye mask, and they were very helpful.
I highly recommend this studio, if the location suits your needs. The hosts are really wonderful and interesting, the location (Condesa) is a great neighborhood in the sprawling mass of CDMX, and the studio itself is cozy (in a good sense) and clean and well-stocked. I can't wait to go back!