Our family of 4 (with 2 small children) spent one week in Ta'Kolina. We had a lovely stay, the house offers all the equipments required, and we had plenty of space. Raymond, the owner, was really reactive and useful, and kindly stopped by to greet us on the last day of our stay.
In-Nadur is a quiet small town that doesn't offer many food stores or activities, but it's nearby Victoria and Gozo highlights are easily accessible. The only small improvement that could be made is a secured pool for children safety, but we managed this pretty easily by staying nearby and closing the doors.
We would highly recommend a stay with your family in Ta'Kolina.