My boyfriend and I have recently returned from a long weekend staying at Daniel's place and we would highly recommend!
Seville as a city was great - lots of different cultural things to do. The Alcazar Palace and Catherdral being highlights - I booked tickets for these online before we went which I would recommend doing as there were long queues for those who didn't. The only thing we did which we wouldnt recommend is the boat trip along the river, really not worth it as there is not actually much to see from the river. The food and drink is another highlight - there are tons of great tapas bars all over and really cheap - only $20-30 between us for food and drink (beer and sangria!). We tried to go to places where we could see locals sitting and there were lots close to the apartment or towards the old town. Literally 20 seconds from the apartment is a bar that is really buzzing with locals spilling out every night (but dont worry, not too loud to sleep or anything!). Breakfast in a local cafe is a must - toasted fresh bread with garlicy tomatos and serano ham with coffee is the speciality! And if you wanted to pick up your own bits to eat there is a supermarket directly across from the apartment.
The apartment itself was perfect. Clean, spacious, big comfy bed. And the location a 10 out of 10 (15min walk from the central Cathedral but enough in the local area that you get a real feel for the city). It's walking distance to everything. And the rooftop was ideal to come back to after a day of exploring to relax for a few hours before heading out for dinner. The water in the pool wasnt heated so too cold for me but I can imagine during the really hot June/July/August months it would be welcomed!
Overall, really great value and would definitely recommend.