Nacho's place is great for a short stay in Seville! The apartment is on the ground floor, but has thick curtains that offer privacy, and there is hardly any noise at night. Check in and communication with the host was great. In the apartment, everything is clean and in working order, and the only thing I missed was a dish rack to dry the dishes. Having air conditioning was a blessing! There are a few small supermarkets around where you can buy supplies (El Jamon is the largest one, but Carrefour express are also reasonably stocked). There are also a few cafes and tapas bars very close to the apartment; although we didn't go in, they looked attractive and reasonably priced.
All major sites are within walking distance, but if you are staying for longer than 2 days, you may want to rent a bike. Our feet were killing us after 2 days. :)
We went to/from airport by bus (EA) - I would recommend to use the stop at Santa Justa, which is just about 15 min away. Make sure that you have cash (small change) for the bus. Per internet's recommendations, we booked tickets to all major sites online in advance and were very happy that we did so - we saw quite a few people being turned away because they haven't pre-booked. All in all, we had a great time, and we would recommend Nacho's place to our friends.