I stayed here for just two nights between cities, but I have been in Mexico City for a year and would definitely recommend this place. I personally loved the "feel" of the apartment -- quintessential of Old Centro but with with special aspects of an artist's residence. The balconies overlooking the historic road and surroundings just two blocks from the Zócalo are great too.
Rubén is also a very accommodating host and took care to make sure we did not need anything. All in all, I would definitely look forward to another stay. Thanks, Rubén!