I have the 66i. If I were to do it again I'd probably get the mini that connects via your phone. the 66i has the 'oh shit' button. I think the mini does too. I posted some comments about my unit on another thread a year or so ago.
Especially when I'm out with my son I really like having the 'oh shit' button. We go over how to use it before every hike or drive into places with no reception. Makes him feel better.