This is a tough one, but going by what I have actually carried and used:
Leatherman Charge AL
Leatherman Charge TTi
Leatherman Charge Ti
Leatherman Surge
Leatherman Signal
I would miss all the rest dearly, but these are the ones I keep coming back to.
My leatherman tools are "Bash em" tools, for use on all the rough stuff.
I have a wave that has seen all the hard times
two wingman tools that are getting a little tired from all that I do to them
and a small pocket tool that i keep having to repair.
They are quite tough, but I find my Victorinox tools much sharper, and better suited to more precision type stuff.
And if I go for heavy stuff, I prefer to use the correct tool.
My leatherman tools are for emergencies mostly.