Perfect location at the top of Passeig de Gracia, 2 minutes walk from Diagonal Metro station. From here it's a 20 minute walk to Plaça de Catalunya or La Sagrada Familia. The apartment is spacious, has amazing views from the 4th floor balcony, is well equipped and comfortable. There are 2 large shower rooms, two comfortable double bedrooms, and a large kitchen / living room / dining area.
The only negative points are the size of the elevator (it just fits 3) making it a little slow to get luggage up to the 4th floor, and we found the hot water pressure a little temperamental.
I would not hesitate to return or to recommend to others. The service provided was great: keyless entry via app, courtesy messages to ensure we had safely checked in when our flight was delayed, and online collection of the mandatory city tax and personal info.