We really enjoyed Castellar Apartment, where we stayed for most of November-December 2014. We did not get to meet Jose Luis, but were very pleased with the help provided by Marina who was there to welcome us at the apartment, and who we were in contact with during our stay. Marina speaks very good English and was helpful with all our questions.
The description of the apartment is accurate, everything worked well, and a lot of information in the form of maps, guide books, etc. is provided. The kitchen and bathroom are well designed, with good space even for a longer stay. The big closet along one wall of the bedroom was also very good. The Wi-Fi worked very well.
Although it is a two bedroom apartment, the upstairs sleeping area is reached by a narrow set of stairs and is open plan with no railings. We just used it for storage, which was great, and absolutely fine for our purposes. It might be more difficult to use as a bedroom for an older person or for young children.
Castellar is in an authentic neighborhood, well off the tourist trail. We were keen to use our (rather basic) Spanish, and local people were helpful and patient with us in this respect - rather than switch immediately to English. We liked that. Food stores and some very friendly bars and restaurants are available locally. The street was generally quiet, with very little noise from traffic or people. We walked everywhere. The city centre (cathedral, Giralda, etc.) is a 25 minute walk and the main shopping areas are just a 10-15 minute walk. The lively Alameda area, with many bars and restaurants, is just a 10 minute walk.
We would be very happy to stay at Castellar Apartment if we return to Seville in the future.