I highly recommend Ulises's apartment. My wife and I stayed there last week during a five day vacation, and we found it to be a great base.

The location is excellent, just one minute away from La Latina, Cava Baja, and the more touristy Plaza Mayor. The apartment was spacious and clean. It had plenty of space to cook and store everything. The fact it had a washer and good air conditioning helped as well. We didn't meet Ulises, but he responded to our messages almost instantaneously. The only caveat is there are a good bit of stairs (4 flights) to get there. However, that should not impede most people from enjoying this apartment. Good experience overall.