Great communication from the hosts prior to the stay. They also sent a link to book an airport transfer - we used this for our home flight as we were leaving at 4am, and it was very easy, paid online and great communication from the driver.
The apartment is in a great location - very close to the beach and plenty of nice restaurants and bars nearby. There are also several supermarkets and shops for essentials. It's a short walk from the marina and Gothic Quarter, and is a safe location.
Maybe take some ear plugs as the bin lorries seemed to drive round the area very early every morning and can be quite noisy and you can also hear the comings and goings of other residents, although obviously this is to be expected in an apartment block.
Would stay again during another visit to Barcelona.