We would recommend staying at Merce & Jepis's lovely apartment as it is spacious and has everything you could possibly need for your stay in Barcelona. The large verandah is an added bonus.
The location is ideal if you want to stay in a quieter area but there are still plenty of restaurants nearby and is just a short trip on the metro to the main tourist areas.
Merce & Jepis were readily available, via phone/email, before and during our stay to give advise if needed.