We visited Barcelona with my wife for a few days and we were very happy with the stay at Christina's apartment. The room is simple, but it fitted our needs fine as we were basically there just at nights.
The location is a little bit off the centre, but we actually liked that it is not in the touristy neighbourhood and maybe it is a bit more quiet. Anyway, it is just 15 minutes to the centre by metro, so this was no problem for us.
We have enjoyed the terrace with a great view very much - either for a nice breakfast or a quiet drink in the evening :)