Bests & Worsts Reviews from Amazon

I bought this product for some shed storage. I needed space for my heavy tools and construction supplies. It does indeed assemble in minutes as advertised, no fuss, but the shelves were just thin particle board, covered in a waterproof composite. Still, the box and description said it was rated to 4000lbs. I had the lower unit in place (it can be assembles vertically and horizontally) and placed two 5-gallon buckets of plaster on the lowest shelf on one side. Each weigh about 40-50 pounds, and instantaneously the shelf began sagging under the weight. I came back a few minutes later with two more buckets and the lower shelf was already cracked! Unreal. How on earth is this thing supposed to handle 4000 lbs?! It's a joke. I was expecting to put four of five five gallon buckets on the bottom shelf but it cracked with just two. Waste of time and money. If the shelves were plywood or you only had light stuff, it might hold up, but I don't see they can make the claim that this holds 4000lbs.