I found the box fairly easy to assemble, but you need to use a power driver to put all the screws in. Do not try to do it by hand. Also, the screw heads were a little big compared to my driver heads, so you have to be careful not to strip them out.
It is a super sturdy box! It will easily handle any workout requirement and is easy to move around. Very solid and reliable. I bought it after using a less stable box and having a painful fall!