This was a very pleasant stay! Omar was extremely kind and helpful, and was an exemplary host. The room was small but comfortable with soft double beds, and the shared bathroom was always clean and quite nice. Omar and his mother Mercedes also offer breakfast for 5€ per person each morning; it was a truly wonderful breakfast and well worth the price.
The neighborhood itself isn't especially scenic or inviting, but it's not bad either, and the house is within 15-20 minutes walking to just about anywhere you want to go (make no mistake, Seville is a city meant to be walked). Also, know that the room is on street level, so you may have some noise from cars or passersby.
All in all, it was a great stay. Both Omar and Mercedes do a great job!