Having a holiday home in Malta, I'm a frequent visitor and know a few locals. One has advised me that he uses Diamond for aircraft hire. Since I'm only in the early stages of my PPL, I haven't had any experience flying in Malta yet.
The chap who uses Diamond has offered to take me for a flight next time I'm there (possibly September time) but this will probably too late to offer you any better advice. I could ask him for some more information for you?
There are a few topics on this forum from a few years back regarding flying in Malta but I'm not sure how relevant they are now.