We stayed in the apartment for four nights and found it to be lovely. It was as shown in the pictures and described, also very bright, with two light wells that brought natural light into each interior room and the hallway. There are two separate bedrooms that close off for privacy. The additional fold-out foam sofas are in a room off the entry that one needs to pass through to reach the bathrooms, or in the living room. So while the apartment certainly has enough space to host 8-10 people, only the people staying in the bedrooms will have privacy.
As others have suggested, the location is excellent, near the corner of Carrer de Valencia and Passeig de Gracia. All of the high end shops are located nearby, but small, moderately priced restaurants are close as well.