We had a lovely short stay in Michael's apartment in Valetta in early April. The apartment has a real traditional feel to it, with thick brick walls and wooden beams, and is stylishly decorated with a modern touch.
Michael kindly picked us up from the airport, which helped to quickly get to the apartment, find our way and start enjoying our break.
Valetta was a little quiet for our liking (esp. in the evenings), but perhaps that is just what you want (e.g. in high season). It certainly was a good base for exploring Malta by public transport, as the main bus routes go from here.