My girlfriend and I stayed at Joaquim's place for four nights and really enjoyed it. First off, check in was smooth and fast. We noticed right away how clean the place was when we arrived which is always nice. This applies to all rooms in the apartment and the building itself. Very clean. The building is also secure. Communication with Joaquim was also good - always a quick response to emails. The apartment is exactly as described in the ad. No surprises.
Next up, location. As other reviewers have mentioned, the beach is literally a 5 minute walk away. Perfect for a morning dip. There is a metro station (Poblenou) about a ten minute walk away. This is the L4 (yellow) line and can get you to the Gothic Quarter in 5 or 6 stops. Very convenient. We really enjoyed the neighbourhood. It is a little out of the way of the busy tourist area but still has plenty to offer. Aside from the beach, Carrer de Bilbao and the surrounding streets have many restaurants and cafes to choose from. There is a grocery store nearby as well.
There was construction on some nearby buildings but the work was only during the day and did not bother us at all. The area is also fairly quiet at night. It was actually nice to get back to a quiet neighbourhood at night after being downtown all day.
Overall we really enjoyed the place and do recommend it to others looking for a nice place to stay in Barcelona. It was hard to leave!