Probotix just came out with their new bolt-on rotary axis. They have better price, i agree. While looking less solid, the diagonal arm made me think it will balance better. Hp is important but i saw the little rotozip cutting just fine. I'm probably going with probotix. Search probotix 3d and probotix milling aluminum on youtube. They will upgrade to 3x4 at very little cost. Keep this conversation going though