Walter's place is ideal for a trip to Mexico City! We had a group of 8 people, and the space suited us perfectly. It's situated in a very accessible part of the city (Roma Norte), and is near so many wonderful places to eat, shop, drink, etc. The rooms are above an amazing restaurant (Huset) and coffee shop (Homie Cafe), which was also ideal when staying with a group (we were so easily able to get great coffee each morning, and it was just one floor below us!). The noise for being above the restaurant area wasn't an issue, either. The space is also just beautiful - filled with lovely light and plants!
Walter and his property manager, Aline, were incredibly responsive (Aline was always available via text message, and helped us out by sending a locksmith almost immediately when someone accidentally locked themselves out of their room). There was also a maid (Tulia!) who came at about 11a each day to clean our rooms.
If you have a large group or just want to stay in a local setting (rather than a hotel), this is the place!