We loved staying at Matthias' place. The apartment is in a lovely residential neighborhood, with great food and drink options within 3 blocks, but also quiet at night. Very close to transit, and quite walkable. We highly recommend La Tia for dinner and Benigni for coffee - both on Manuel Maria Contreras, one block over.
The apartment is very comfortable, with couches and a table good for eating or working. This may be the first time we've had a full kitchen that actually had all the equipment to reasonably cook - important as we stayed over two holidays where fewer places were open. Washing machine worked great - in cooler weather it did take a little longer for clothes to dry, as there isn't a ton of direct winter sunlight.
Check-in and checkout were a breeze, coordinating with Maria. Great communication and very helpful.
All in all, this felt like home, and we would love to stay here again our next visit to Mexico City.