We very much enjoyed our stay in Maria's appartment. The place is very clean, decorated with taste and well fitted out. The bed is confortable and the bathroom nice and brand new (like the rest of the flat).
Maria is very pro-active and responsive, checking regularly that everything was going smoothly.
As for the location, it is perfect - bang in the middle of Valletta, which means you are in easy walking distance of all the major attractions, and still very quiet.
I can only recommend this place!