I enjoyed my staying at Martha's place. It's very well located, just 5 minutes walking to Paseo de Gracia and 10 minutes to Plaça de Catalunya. The building and the house itself are beautiful and the bedroom is bright and spacious with its own modern shower room. The air conditioning works well and is quiet; the large modern window keeps the traffic noise at bearable levels.
There's no bed, instead there are 2 mattresses on top of each other which was OK for 1 person but honestly I would've preferred a proper bed. Bear in mind that if you are travelling in pair you will basically sleep on a mattress on the floor. Would be perfect if there was a TV in the bedroom as well.
Martha was away at the time but she kept in close contact over the phone to make sure that everything was fine with me. She was very nice, friendly and helpful throughout.