My biggest question is whose last the longest? Fabtech's lasted a year, Rancho 5k lasted 4 months on the fronts on my 6" lifted heavy ass truck.
fabtechs are junk, both white body and their "rebuildable" ones.
Fox or bilsteins IMHO. i dont care much for the ranchos, mainly cause i dont like the valving in them no matter the setting even on the 9000s but im picky. they seem to do well for many others.
in your cold climate, you may need to look into some shock fluid that is a little thinner than the 5wt foxes use. ride will be a little rough and make some noise till the shock oil heats up some. id also put some kind of boot around the shock shaft. knicks in the shaft from rock when you are driving off road are the leading cause to shock shaft seal failure. then you loose all your oil and nitrogen and kill the internals of the shock.
serviceable shocks should also have the nitrogen level checked in them once a year with the shock at full extension.