I would wholeheartedly recommend staying with Alexandra and her family. They are kind, caring and attentive - I felt very comfortable. I had my own room, bathroom and kitchen area. The rooftop is very nice too!
The house is in a lively area close to the football stadium, and the metro station is less than five minutes walk. I found it very easy to travel into the city centre.
Now I've got my own place in Sevilla but if I ever needed to recommend a place for family or friends to stay - I would recommend Alexandra's!