One of the problems with aluminum studs are the welds, some aren't done too well. I think that is where the questions about using on gravel come from. In theory , a wall as a solid piece adds greatly to the strength of the unit. They have been playing around with this technology for while now, so they should be getting it right. But there is reason for the wide range of prices, and it not just the hardwood cupboards.
We have taken ours to Arizona twice, across Canada, into NWT , this summer the Rocky National parks on both sides of the border, of course all over BC backroads.