You don't stay at Mario's just for the accommodation.
You stay for the invaluable insights that Mario can give you into Haz Zebbug, it's history and culture.
You stay for the fabulous village that is Haz-Zebbug, the active and welcoming band clubs, the regular stops at the Lungo coffee shop to shoot the breeze with Philip and the rest of the guys on the pjiazza, and to buy fresh fruit and veg almost daily from Ray and Grace.
There's an excellent regular bus service to and from Valletta and Mdina (and others). It's a short walk from Mario's provided you're not stopping for a chat every 2 minutes.
Mario's place & Haz-Zebbug has spoilt us for every other place in Malta.