This is a well made product, which at the moment works well. My previous 4x4 was exremely annoying as the corner pieces were constantly popping out. This does not appear to happening with the new one. If it gets worse, I will alter this review. I cannot comment on the speed of the cube, as I more of the slow and steady group. As a bonus, I think is a note in the box giving a solution.. However I cannot confirm this, as my Japanese is not up to scratch.