I know most people on the forum are usin the direct drive, Imy machine has two “Z” axis’s:a Hitachi on the B nd C axis and a Makita 700c on the X/Z. I am using the direct drive unit on the Makita and the belt drive model on the Hitachi(mainly to shift some of the weight from the front of the carriage to the back). However, I have found that the belt drive model actually is a much smoother performer than the direct drive model. In fact, at some point in the future I plan on converting the direct drive to the belt drive model. May I suggest that when you purchase your unit that you also purchase the top plate for the belt drive unit? Thank you.