When I started traveling on business, I bought a complete set of Zero Halliburton luggage. That's what people did in those days: buy matching luggage. Over about 15 years of extremely hard use, they got all banged up but nothing packed in them either got wet or broken. The locks and seals all held.
They didn't have wheels. Wheels on luggage hadn't been invented as yet.
What finally caused me to retire them was their lack of wheels and their weight when empty. Entirely too easy to go over 50 pounds. I sold the 30" Zero to a friend who was glad to have it and the rest linger in my storage area.
When I consider the number of trips those bags took, they were a very good value for the money.
One of the most useful items in my Zero collection are a pair of train cases. I still use one now and then for carrying bottles of wine. I would never call a Zero bag flimsy or made of thin metal unless the nature of the product has changed a great deal.
Nor would I buy more Zero. They are bags that no longer serve my needs, although family members have borrowed them when they needed to move! Great for keeping fragile stuff from being broken.