Great location. The flat is a few steps from the waterfront, and a short walk to buses or the ferry into Valletta.
Alberto is very friendly and helpful, and Senglea is quite charming. It's a small neighborhood, very walkable, and wasn't swarmed with tourists.
One thing to be aware of is that, the flat being all stone (which has a lot of character), and near the water, it can get chilly in winter. Alberto has heaters and a dehumidifier, which help a fair bit.
Overall a great flat in a nice residential neighborhood that's well located for roaming around Valetta and its suburbs.