We stayed at Oscar's place for 2.5 months and felt very much at home. The place is very large, which gave us all lots of space to both live and work. We traveled alot on the weekends and the location next to the main train station, and all the car rental companies, not to mention close proximity to the airport meant each of our trips was totally hassle free. Nervion is not the picturesque Sevilla that many dream of, but the neighborhood is very, very livable and lively. Everything you'll need is in the immediate area, plus lots of great spots to eat. We are walkers, so walking the 15 or 20 mins into the center was never a problem for us.
Oscar is an amazing host and will make sure you're well taken care of. Be sure to follow his lead for places to eat. He sent us to so many great tapas places. We really appreciated his kindness and helpfulness!