We've only stayed for one night at the Palazzo but loved the time we got to spend there.
As our host pointed out during our check-in, it is one of the oldest houses in Valletta and you can feel the history when you walk through the bulky entrance door.
There are a lot of plants (and a lot of stairs) that will carry you from the atrium at the bottom all the way up to the roof, where you can chill out in the evening and enjoy an incredbile view around Valletta!