Sid has one of the best reviews AirBNB's in Barcelona. Having stayed there for 5 days, I can see why.
Lets start with the greats
1. Sid's guidebook was incredibly helpful, especially with respect to options for local food. In particular, I would have never found La Patisserie or DelaCrem without his recommendations and these were some of the bet bites of the trip. I'd also recommend the empanada place Rekons which is a couple blocks away as well as Can Cargolet - the snail and rabbit dish was the best thing I ate in Barcelona)
2. Location: Easy walk to La Rambla, the Gothic quarter and the cathedral. The Aerobus has a stop immediately outside the apartment. Metro is on the same corner.
3. Good price for the area, especially given the size and the amenities
4. Comfortable bed.
Couple minor areas for improvement:
1. A desk or a kitchen table would be a nice addition.
2. WIFI was spotty, however, I think this is an issue for Barcelona as a whole rather than the apartment. Never found really good connectivity.