My family stayed at the apartment belonging to Costa Azul during our 2-night stay in Granada.
The hotel's location is perfect. Very close to the Cathedral, close to transportation that can take you to Alhambra, and nestled perfectly amidst shops and restaurants. Everything was walkable, even Alhambra, although I'm happy we took the front desk attendant's advice: Take a bus to Alhambra, since it's all uphill. Then on the way back, walk downhill.
If I'm not mistaken, the hostel has rooms in its main building, and also has an apartment located across the street where you can rent out the whole floor.
My family (5 people total) stayed at the 2-bedroom apartment on the 4th floor of the separate building. It was perfect for us. The small kitchen had enough of what we needed: fridge, sink, cupboards supplied with utensils, hot-plate, and washer (for clothes, not dishes). We prepared our own meals most of the time.
Also, the apartment has a roof deck which is spectacular! You have a view of Alhambra on one side, and the Cathedral to another. I slept on the roof deck one night, but it was too cold to do it a second time. The apartment had enough beds for 5 people (1 queen, 3 twins) so it was perfect for us.
The staff was phenomenal and supremely helpful. We were there during the Fiesta de la Cruz, for which the staff had prepared festivities in the hotel. They were extremely busy preparing for it all, but that didn't deter them from helping us out with everything we needed. And as busy as they were, they provided all the service needed with a smile. Kudos to them!
Also, on internet, I was told they had WiFi, but I never checked. There was wired connection in the apartment (only one) so that was enough for me.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.