The "family suite" basically is two minisuites with one large sitting room and one large balcony. It retains two complete heads. On one side, the bedroom is a standard bedroom configurable as either two twins or a queen. On the other side, the bedroom has twin lower and upper bunks.
If you have two or more children, the "family suite" probably be the better arrangement. If you have four adults in your party, get adjacent minisuites instead and have the steward(ess) open the partition between the two balconies. In the Vista Suite, the accommodation for more than two passengers is a sofa bed in the sitting room -- certainly not an ideal arrangement!