In this ever changing data grabbing world the only thing that is constant is change. Whatever you decide now will be out of date in three years time. I still have the floppy disk with my father's first computerised tree on it from 1994. I also have the paper copies of the information.
I have the trees in FTM(Family Tree Maker) because I was given the original as a Christmas present. In PDF on a stick, and printed on paper in every format the program allows. I have bits of trees on FMP and Ancestry and Genes reunited simply because I figure that if they all fail at the same time the world will be coming to an end and while that is happening I can be printing one more copy for the fireproof box.
Oh and I have the backup on an external drive - forgot about that.
Whatever we do it will be the printed on paper version that is the only one guaranteed to be readable in 30 years, and then only if you have used indian ink on acid free paper