We spent 5 days in barcelona this Augusts in Beatriz's flat.She has a very beautiful,spacious, cosy, quiet place in good proximity to public transport and local shops. Metro and busses are about 5' walk from her doorstep! She is very gentle and desecrate as host and very good in communication as well!!
However if you plan to visit during hot summer days, bear in mind that the place has a small fan that dose very little. Apart from that, this is a very beautiful place, with a very nice host!!