Luis' place is fantastic. It's clean, well appointed, stylish, and has a great view. Plus it's super close to most attractions -- almost everything (sights, great bars, wonderful restaurants) are within walking distance, and for those that aren't, the apartment is very close to two different metro stops. Additionally, if you like cabs, a steady stream goes by the front door.
Luis is very helpful and very fast to respond to any questions. He left a bunch of suggestions and guides for us and even included a nice bottle of wine!! 10++!