I have no idea why people hated this product, maybe because it was hard to understand how to assemble the bed, but the main problem that this product has is the base of the bed has three parts that should be pressed to the bed frame to be installed properly. I am not sure that would work for long time because the part that attaches the mat( wooden covered with cotton) is very small and looks dangerous, it can be broken easily ( as I guess ).
You also can not use a big mattress with this bed frame.