Both James and his place are excellent. The house is located in a prime spot in Polanco, nearby several major marketplaces, and providing easy access to everything. Uber is going to be your friend in CDMX anyways.
The apartment has a ton of great amenities, including gym and jacuzzi - these are great additions. The rooms themselves were very comfortable, very spacious and clean.
James is even better as a host. He and his wife were there to greet my friends and I, and he was continuously accessible throughout the day. He would respond to any questions I had instantly (within 3-5 minutes, max), and the people in the lobby were equally as helpful.
If you are concerned about staying here, be concerned no more - it is the perfect spot. For Americans thinking they need to be in Condesa, it's really not an issue if you use Uber - and the many amenities make it worthwhile anyways.
I hope to stay here again soon!