Our family of five adults stayed four nights. The beds were exceptionally comfortable and the rooms have blinds to make them dark any time of day, so everyone slept really well. The front bedroom gets some street noise but was entirely manageable. The location is good but requires a fair amount of walking to the major sites. It’s definitely a walkable distance, but you need to enjoy walking (we did).
I would not characterize the neighborhood as an historic area but within a few blocks you can find narrow, winding streets and a lot of character. Same goes for restaurants; lot of options in close walking distance and somewhat less expensive than the central tourist area. We also loved that the unit lets you observe Sevillianos in their living environment.
The location of the unit is ideal of you are arriving by train (Santa Justa is just a few blocks away). The kitchen was very nice and included a Nespresso-like coffee maker. Unit also has a big dining table and a nice TV.