Like many others, I found this extremely hard to assemble -- because the screws were too short. I ended up ordering some M6 55mm Flat Head Screw Bolts (to replace the long ones) and some M6 35mm bolts (to replace the short ones) and they worked perfectly. 

Once I replaced those and the allen wrench (4mm), it assembled with relatively little difficulty. Seems to be sturdy, may try to update in the future, when I've gotten to use it for a few weeks.