I am on my 7th design iteration.

My question is regarding motors. Is there any reason not to just use a servo on one axis?

My thinking is that if I go the two X axis motor route, I can probably buy a servo + drive for roughly the same money as 2xnema and 2x drivers.

Upside of this being I could run a heavier gantry (120KG).

I am thinking I'd see more single servos driving an X axis, and steppers the rest, if that was the case?