My friend and I spent a week at Rosa's and George's guesthouse and had a lovely stay. Everything is completely as on the pictures and in the description. Rosa provided us with many nice tips for our travels and was super friendly. Location is perfect, well-situated in the center of Valletta.
The only downside was that the room was very hot because there is no AC. But we had a fan in the room.
We really enjoyed our stay and would totally recommend the guesthouse! :)