We are a family of 5 adults and found Holger's apartment to be spacious, elegant with tall ceilings and modern facilities. It was clean and well equipped but not so immaculate that we didn't feel at home and able to relax. The bunk bed, whilst not an issue for us, had a very steep ladder.
The WiFi was sometimes patchy so we were unable to use Netflix. A/C was efficient but we did have to reset the bedroom control a few times.
The apartment is in a fantastic location, there was some street noise but we expected that due to its central position. There were plenty of good restaurants locally.
Guille who met us for the check in was very helpful and gave us lots of useful information for getting around the city.
We would recommend the apartment as a great base for exploring Barcelona.