Despite arriving at the flat at 5pm on Christmas Eve, we were greeted graciously by our host with restaurant tips, parking advice, and suggestions for day trips.
The flat itself is very nice, with tons of windows and natural light. The beds are comfy and each room has it's own hot/cool air unit.
The location is also fantastic, we stayed 4 days and wished we had longer, as the apartment is the perfect place to start a walking tour - in any direction! You are right smack in the middle of everything.
If I had one complaint, it's that the wifi was not great in the bedrooms, but strong in the main room. Also, given the amount of windows, some street noise does come into the apartment, but by bedtime things are very quiet. By all means, stay here while visiting the AMAZING city of Seville!