Our DD rode both of these from the time she was tall enough, 3.5 yrs, and they were immediate favorites. I think that first year we rode BTMR about 5 times, including 3 in a row on E-Ticket night. When she was 4.5, we rode it 11 times over the course of a week.
Of course, now she's tall enough for Space Mountain, so that's the new favorite. Harder to ride it so many times, though.