We had a great time at Mario's appartment. It's in a great location near the bus stop (and the public buses in Malta are cheap and regular) and about 20 minutes walk downhill from the beach. There are a few restaurants nearby and all are inexpensive. It is also close to a couple of food shops.
The appartment itself is clean and modern. It was really nice having two bathrooms and the balcony is big enough to sit on. My only thought would be it would have been nice to have a few more bits there (e.g. tea/ coffee and more than 1 loo roll as we were there for a few days).
My friend and I had to work for some of our trip and Mario was quick to get back to me and confirm the WiFi worked well- and he was right! Overall communication was great, the appartment was great, and I would definitely recommend staying here.