Important: you can't hear any planes
I wanted to start with that as my only worry was noise from planes since it's so close to the airport, but I genuinely didn't hear a single plane during our stay. I cannot recommend this place enough. Lots of the other reviews are spot on about how beautiful, clean etc this flat is but there are few things that made it really special for us.
1. The hosts are wonderful people, gave us the best recommendations for restaurants and things to do (invaluable), gave us us a lift to the coast, gave us some delicious local cheese to try, and were generally very generous and accommodating, while also not being too intrusive at all.
2. Public transport links are ideal. There's a bus a 30s walk from the flat that takes you straight to the airport, the capital and so many other attractions, there really isn't any need for taxis.
3. Ability to be self-sufficient, with local shops a minutes walk away and a nicely equipped kitchen you don't need to rely on eating out.
I'm fully recommending this flat to anyone visiting Malta.