The host is really nice and gave us recommendations and tips to get around the city. He was always available and responded quickly to our messages.
The house is well furnished and equipped. The bunk bed was a little uncomfortable though. We enjoyed our stay there, we had everything we needed in the house.
The house is close to the city center. You can walk to all the main monuments of the city(about 20 minutes). There are also buses that take there about 6 minutes away from the house. But the location is really not suitable if you have a car and that was our case. We normally use our car frequently but the streets were very narrow so we had to leave it in the parking.
I really recommend Carlos' house of you want to have an authentic experience in Seville.