The flat was great for 1, and would be perfect for a couple as well. It was very well kept, spotless. Ulises met me to give the keys, answered my questions, and gave me some general tourist highlights as well as restaurant recommendations. He is very friendly and personable, and was easy to communicate with leading up to the trip.
The flat was in a great location, convenient to the metro, restaurants, and shops. And La Latina is at least not right in the heart of all the tourists, so you get a bit more of a local feel. And on Sunday, El Rastro is right outside the door!
I highly recommend staying at Ulises place!