Fantastic location - a 10 minute walk from the airport bus stop/plaza d'espanya and 5 minutes from Poble Sec metro and lots of great bars and restaurants (we loved carrier de blai).
We had an issue with the travel cot as a duvet was provided as a mattress so it was a tricky first night but Veronica came over with a proper mattress the next day. The air conditioning was also a bit slow to get going but by the 3rd day it had started to cool the apartment much better. The apartment is basic for the price but did the job for us!
Beds are really comfy and we didn't need to use a Blackout blinds as the blinds provided were so effective. Very useful to have a washing machine and somewhere to hang clothes. The things for the beach and little makeup remover were also nice touches.
Little note- there is a lift but it's quite small and didn't fit the buggy in. It wasn't a massive issue and wouldn't bother us at all pre-baby but just useful to know.