The apartment is really well located, we had everything we needed on our doorstep (supermarket, coffee shop, bars and restaurants) and it was a great central location to explore the city from. The apartment was comfortable, especially the beds!
The communication was however quite poor while we were there. We had some issues with out of hours check-in and when we phoned the out-of-hours number they didn't provide any help (they actually tried to tell us we had the wrong number).
Be aware that there is only one key for the apartment, which was quite annoying for two couples staying at the apartment. When we asked for a second key we were just told that wouldn't be possible with no real explanation as to why they couldn't help.
As other reviews have mentioned, there is very little by way of 'nice touches'. There was no washing up liquid and tea towels, tea and coffee etc. Even the kitchen essentials such as salt and pepper (which the listing said was included) weren't there. The property is managed by a big Barcelona rentals agency called SH Barcelona, so you don't get some of the more thoughtful touches that you often get with an individual Airbnb host.