This apartment is about as centrally located as one can wish for in Barcelona. The Plaza Catalunya, Las Ramblas, Gaudi's Casa Battlo & Casa Mila are all in walking distance. The metro is right across the street, as are the Barcelona turistic buses and a taxi stand. There is a very large supermarket also right across the street and a 24 hour smaller supermarket half a block away. Restaurants are abundant, the Gothic quarter is a block away, and I could go on and on. The building is quiet and secure. There was construction on the facade and on the building to the side, but we heard no noise at all during our stay. I could not see anyone actively working on it either; so maybe we just lucked out.
We were a party of 6 - there were more beds than there were people. The design is a marvel of space efficiency. A couple of the smaller rooms may not fit taller/larger people very well, but we were just fine in every room. The home was clean, everything worked. The instructions were very good - in fact, there was even a folder that explained how the washer, dryer, and dishwasher worked.
A few improvements would have made the stay more than perfect. We got two garbage bags and 3 tablets of dishwasher detergent upon arrival. All 6 guys in our party ate breakfast in the house every day - that meant we had to use the dishwasher once, and sometimes twice daily. That was just not enough for us. Since the apartment is built to accommodate parties of 6 or more, saving them the trouble of having to buy a whole dishwasher detergent pack for 4-5 days of stay would be a nice gesture. We just used plastic grocery bags as trash bags - so, the trash bags are not an issue.
Overall, the check in process was great, instructions were great, apartment was great. Wonderful stay.