Had a wonderful three night stay at Bárbara's place with two friends. The space was very comfortable, and had everything we would have needed and more. There is a full kitchen and a laundry machine/dryer for those who would need it. (One thing which wasn't a problem for us, but could be for larger groups, is that though there are 2 bathrooms, there is only one toilet and one shower - but once again, we didn't have any issues).
It's conveniently located less than 5 minutes away from metro and bus stops, and surrounded by grocery stores/cafes/markets/shops. Bárbara gave very good tips about areas to explore, and provided a whole booklet of restaurant recommendations (we tried 5 or 6 of the places listed in the book and enjoyed every one!).
She was also really accommodating with our check-in/check-out times, and very considerately allowed us to keep our suitcases in the apartment after our check-out until we had to leave for our flight.
I would definitely recommend this place to anyone planning to visit Barcelona :)