We stayed here for a few days on our honeymoon and it was EXCELLENT. I definitely recommend using their shuttle service if you are doing a lot of moving around or have a lot of luggage- Fransesc the driver was very kind and helpful and got us to and from the airport quickly. Judit in the office was extra helpful getting us checked in and oriented. We met a few more people who were also extremely helpful and nice as well.
As for the location- it’s LITERALLY in the backyard (well- side yard in about 8 years I guess) of Sagrada Familia. The apartments are definitely a good amount of space for 2-3 people and maybe a few more if you have kids. The air conditioning seemed sufficient in Late August, and we didn’t have any problem with street noise. There were plenty of restaurants and stores nearby, as well as easy access to the metro and Cabify/Uber. I don’t know if it’s in a trendy area or anything, since we didn’t spend a ton of time in the vicinity, but it made a great home base and also easy logistics. I would definitely stay here again, and will recommend to anyone I know going to Barcelona.