I have spent a wonderful 3 nights in Carlos and Antonio's place. It is truly a fairy tale place with lots of cute, vintage furniture and charming paraphernalia. Everything in the kitchen and bathroom is perfect for the guests. The one thing that is true is that it can be noisy. Actually, the street is not noisy at all, it is small with no trafic. However, due to the thin walls you do really hear every person walking down the street. I had my earplugs but the guys are so great that they prepared some for you in case you forgot yours.
Carlos and Antonio were very welcoming and friendly. They invited me to a birthday party but since I wasn't in Sevilla alone, I have never made to it. A real pity!
The flat is perfectly placed, close by walk to the party scene and easily accessible by public transport.
I can definitely recommend it and will stay there again, should I go back to Sevilla again.