We had a great stay at Alex's rooftop apartment. The place was perfectly adequate for our stay- we were out exploring Mexico City the whole time and only came back to sleep- but it didn't exactly feel luxurious or super comfortable. It has everything you need and a nice, sunny veranda to go with it, so for this price it is a great deal. Location is quite good, near popular areas of Roma Norte and close to the Ciudadela market too. It is up quite the flights of stairs and a spiral staircase, so if you have a lot of heavy bags it can be a bit tricky.
Their communication with us was perfect, we felt safe and like there would be someone to help us the whole time.