We stayed at Zona's flat for 3 nights. It was quiet and very clean, and she provided breakfast and sweets, which was a really nice touch. We only saw Zona when we arrived but she was very quick to respond when we had questions. The bedroom was a bit chilly despite the heating in the living room, but it must be nicer when the weather's warm.
I'd definitely recommend staying at Zona's if you don't mind having to take the bus to visit Malta, since there isn't much to see in Msida, but it's still fairly close to Valetta's main bus station.