Matt and Julia were excellent hosts and my girlfriend, sister and I had a great stay for about a week with them. Lish was a lovely dog too.
The location was great for us, being near Valetta, some of the busier social scenes but also a wedding we were attending. That said it's a small island and it's not too bad to get around anywhere.
In terms of the boat itself, it was even better than we were hoping for. Electrics all worked fine (you'll need European adapters). WiFi was great and allowed me to get a bit of work done when I needed to. Choose the room with the aircon unit available if you struggle in the heat at night. There was a small bar on board with fridge for drinks and honesty based policy for payment of drinks.
It was pleasant surprise to be able to go out on a boat trip in the smaller boat Matt and Julia have. We went for a swim with the dog who they take out daily. My girlfriend and sister also got a lift to one of the hotel pool bars on another day! Just a small contribution as a gesture towards some of the petrol. The suggestion is around €20.