Ok, just when I thought this question was asked a billion times, here I go asking it.
I read through the owner's manual that the dealer gave me for my CC 29RE and noted that: "be sure the jack is placed firmly against the chassis frame"
in a highlighted WARNING section.
So now when I go purchase new tires, I will have to deal with the tire store as to where to palace the jacks to change out my tires. They will most likely want to place the floor jacks under the axle. Some seem to suggest lifting both axles on the same side to distribute the weight. Others use some sort of Tandem Tire Changing Ramp gizmo, and there are even some that suggest that the 6-point leveling system (not recommended in manuals) is the way to go.
Is this question similar to: which truck is better, Ford, Chevy, RAM?