Actually, Colorado is built on the Isuzu world truck chassis. GM, in its infinite wisdom, pulled out a great 4 cylinder diesel that Isuzu had in it and shoe-horned the terrible I5 in its place.
My Axiom is a "fancy" Rodeo with different sheet metal, stiffened up frame, adjustable shocks and a multi-mode transmission. I love that truck. Gas mileage is not the greatest, but it will plow thru 2' deep snow like it's not there.
I have not had any problems with suspension on my Axiom (knock on wood), but I did get it undercoated soon after buying it, and AK DOT does not use salt on the roads.