You definitely should stay at Manuel's apartments, they are located in a calm place but very close to all interesting sightseeings. You will also receive great advices re: where to eat, what to visit etc. Manuel is very helpful and answers all questions. Also, please note the free parking – I don't think that you find a parking place in a Seville by your own - this is a quite tricky process.
The home itself is nice and clean - it has everything you could ever need.
I suggest you to stop your search and just book these apartments.