As long as the bike never falls on the aluminum bags they will do fine.
I've landed my 950 on my Caribous several times and they are no worse for wear and tear.
After reading a lot of reviews the single common aspect of all the metal boxes were that eventually I would read of someone tweaking them and then being unable to close them. Several of these reviews were folks on world tours.
Some were able to bend things mostly back into shape, others had welding done to repair the metal case. Many reported the cases never sealing properly again.
Bottom line is that this is considerably less likely to happen with cases such as those offered by Caribou Cases or other Pelican-style bags.
Aluminum is prettier and looks great on those GS's at Starbucks, but in the real world there may be a few drawbacks worthy of consideration.
Go to the vendors forum and read ALL the posts for any set you are planning to pay good money for. Then decide.
This is The Internet. Confirm for yourself anything you may see while visiting this strange and uncertain land.