The four of us (2 couples) stayed at Marta+Paul's place for 3 nights. We all really liked it. Very comfortable stay and nicely renovated. Apartment was super clean-- just the same as the photos! Paul was the one to meet us for check-in and he was super friendly and helpful. He was always very responsive as we continued to stay in touch via WhatsApp for questions and comments.
I'd highly recommend their place for your Barcelona stay!