Maria's apartment is superbly located--right around the corner from the Cathedral and the Giralda. But, being on a pedestrian-only street a block off the Cathedral tourist circuit, it is very quiet--except for the lovely street music below (which you can listen to on your small but charming balcony).
The apartment is small-a studio, really. To be expected in European environs, but small nonetheless. The bed could use an upgrade--it's 2 well-used twins pushed together. And you've got the normal complications inherent in the owner not being on site (I believe they live in a different part of Sevilla).
Those warts aside, it's a lovely little gem in about the best spot possible for enjoying a few days in Sevilla.