We were the first guests at this apartment, after Elena and her brother Antonio renovated it. There were a few hiccups with being the first occupants, but ultimately we were extremely happy with the apartment, and especially with Elena and Antonio's responsiveness. They were extremely helpful and knowledgeable Sevillians, and speak perfect English, if that's a concern. The fact that it belonged to the painter, and that you can go to the museum and see his work, is an added bonus.
The apartment is a few steps off one of the busiest walk streets in the Santa Cruz bario, just about 200 yards from the Cathedral. You couldn't be more centrally located. However, because it's off the street, it's actually quite quiet and peaceful once inside.
The apartment is three narrow floors. The first floor is the kitchen/dining and living area. The second floor is the "master" bedroom and nice-sized bathroom. The third floor is another nice bathroom, and smaller bedroom, and a large deck with a straight-on view of the Giralda (tower). All the floors have many windows, opening out onto the courtyard or the rooftop deck. The beds and furniture are all newish (except for the obvious antiques) and very comfortable. The wifi worked great.
We were there for Easter, which in Seville is like being in New Orleans for the Super Bowl in the US. They ring the bells in the tower seemingly on a whim, and they are loud. When it's not a holiday things are calmer.
We really enjoyed our time (5 days) in Seville, and the apartment (and our hosts) were a big help in that. Once you learn your way around the maze of tiny streets, you realize you couldn't be in a better location. And in the apartment, once we learned the peculiarities of the European appliances, et.al., we were very comfortable and pleased. You can't go wrong with any of Elena and Antonio's apartments (we toured the others also). I would highly recommend them.
If you're coming in from the airport, and don't know your way around, just take a cab and give them the address. You'll never find it on your own. Once you figure things out a little, you can step up to the challenge of finding your way all around the old town. There is a tourist info place right next to the Alcazar (which is maybe 500 yards from the apartment). They have maps, which you'll want to keep with you. It is both fun and inevitable that you will get lost at first. BTW the Seville metro is almost brand new and top notch. There are a dozen good restaurants and bars within 40 yards of the apartment. Like I said, the location is basically ideal. You can go days on foot and see all the sites.