We loved the flat and the location! It gives you the feeling of being a local. We found it was a great starting point to explore the city; take a dive in the nearby bay to start your day, than off to the bakery (Frendo's) and have your coffee on the balcony watching Valetta waking up.
Mark gave great advice on what to do and where to go, helped us out big time when needed with our tickets and took care that the apartment had all the facilities we needed (and more).
p.s. if you're sensitive for noises bring earplugs for the night (at least for a saterdaynight).