I have seen well maintained 20 year old rigs and others that can trash a rig in 2 years and everything in between.
If you don't do maintenance don't expect it to last very long.
I would agree with Rexlion statement.
The more severe use it gets the more problems your going to have. A ultra-light would be one of the worst choices for rough use, they are built for light weight not durability.
My opinion. I would look for who had the best frame and most weight capacity.
Kind of like asking if a economy car would hold up as well as a Land cruiser on the trails.