Even with careful attention to every detail, assembly was difficult. I also swapped the laptop arm and monitor arm, but only after everything was set up. So I had to take it apart and redo it. Also, tighten everything as tight as possible! It wobbles when you don't, but when tightened properly everything works as it should. Such a reliable little setup takes an hour or two to assemble. I have Mount It! VESA Mount Adapter for my external USB monitor and it works very well! All in all a good setup, tedious to assemble but you only have to do it once! worth the effort :)