This is the private home of an art and antique collector. The tour was informative and friendly, although it would have been much nicer if our guide had offered water or something to drink, as we had to wait several minutes while the previous tour ended. The owners were out of town, so maybe the tour with them is different.
€8 is expensive just to look at someone's collection, but we decided to do it anyway because of the reviews. I enjoyed the tour, although I think €8 is asking a lot to subsidize someone's collection. It felt more like walking through a well-curated antique shop than anything else. If you are a collector you might find it worthwhile. If you are only mildly curious, I would say skip it. My boyfriend was practically falling asleep, he did not find it interesting at all.
I appreciated the art and artifacts the family has collected and the stories behind them, but I would not consider this a "must," especially given the heavy cost output in addition to seeing Heritage Malta sites. There is plenty of free eye candy just walking around Rabat and Mdina.
This review is the subjective opinion of a TripAdvisor member and not of TripAdvisor LLC.