The location is great. Be aware that if your flight or plans delay you, there's a 20euro charge after 6pm. The apt is secure and has an elevator. There's a swirling staircase that can make it feel dizzy to some. You'll be taking the stairs more than the elevator.
Friendly staff. Felt like a little hotel. We did have an issue with the shower drain. It was clogged and we were able to have someone come fix it, slightly. But the maintenance person didn't clean up the mess made from the unclogging the clogged drain.
The space is small, but was fine for the 2 nights we spent there. The big draw is its proximity to La Sagrada Familia. You can see it from a few rooms. Three bedrooms and a sofa bed in the small living/dining room. The beds were very firm. So some of our party had sore backs in the morning.
The avenue it resides in has plenty of food options. We loved the gelato sandwich place next to the building.