We stayed here a month in April-May and loved it! The neighborhood is quiet and authentic, away from glitz and tourists, but the nearby bus line and ferry make it easy to get anywhere on Malta. There are restaurants all down the waterfront, starting steps out the front door (we particularly liked Tully's). Senglea itself is a quiet city that feels like a village, but upscale supermarkets and modern stores are just minutes away by bus. Having spent the month traveling around most of Malta and part of Gozo, and in particular visiting Valletta often, we are very happy with this location for our home base.
The flat is even nicer than the photos show. The kitchen is spacious and easy to cook meals in. The high ceilings and floor plan give it a relaxing, open feel. It's a modern home, in an old building in an old city: great combination. Peaceful and dark at night (nice for light sleepers like us).
Richard was highly responsive to the minor issues that we had.
We spent most days with windows open and bugs weren't a problem, at least at our time of year. If you come outside of the warm season, bring a sweater for after sundown.
We miss the place already!