We've spent one month at María José's flat and everything ran very very smoothly.
You cannot find a better position in Sevilla: on a quiet narrow street but absolutely central, 5 minutes walk from the Cathedral and the very lively Alfalfa and Salvador squares.
Also lots of bars, restaurants and supermarkets in the neigbourhood, as well as a daily farmer's market to grab fresh fish and vegetables.
The flat is perfect for 2 and has really anything you need - also for a longer stay like ours. In between two patios (one communal and one private, the latter perfect for having lunch and your last cold drink before sleeping), the apt is very quiet and cool - you won't need any AC even in hottest Andalucian summer days. For the same reason, the apartment is very very safe.
María José is the perfect host: she lives in the same building and can help in anything you need.
Just one small point: should you need a fast WiFi for working there, as we both did, you would probably need to get your own hotspot as the line is weak and slow due to the thick walls - but if you stay there for holiday it isn't a really a big issue: just go out and live the city!
We enjoyed our stay a lot and recommend strongly the place. Gracias por todo y hasta pronto!