servo or stepper size selection

I have an old mill (1965 index)in great shape it is 9 x 40 and its
lead screws are 1.125 dia. .200 lead i am planning to change the lead
screws to ball and cnc of some sort. I have a pc for the job now im
looking for best or should i say reasonable way to go, servo or
stepper ive been on ebay and looked at many sites for home cnc. I
want to have an accurate and reasonable to program cnc setup
any help would be appreciated. thanks --mark