My family and I stayed at Quim's apartment during our visit to Barcelona, and had an excellent time. The apartment itself is very cute and well located in the heart of Barcelona's historic downtown. Quim was an amazing host - always responding promptly to all of our requests and ready to help.
The only issue we had was related with the digital key, which, because of the fact that it malfunctioned, inhibited us from entering the apartment a couple of times. However, aside from that, our overall experience was AMAZING, and I would warmly recommend Quim's apartment to everyone.