We've found no flaw in the bed frame so far, so the 4 star rating is meant to show that the bed frame is successfully performing its purpose.  It's sturdy and it was easy to assemble, though I didn't follow the instructions because it was simply easier to put together in different order of assembly.  It's used in a small bedroom, so we enjoy that it takes up no more space than the size of our mattress, and the extra storage space underneath the bed is great.