Lots of people have made extremely impressive machines with ACME screws and stepper motors. These components are perfectly suited for hobby and light industrial cnc machines, and in general offer a much better value than ballscrews for people interested in doing cutting tasks that don’t require +/-0.001″ accuracies or better.
While ballscrews are more efficient, high pitch ACME also runs smoothly and does a great job of converting rotational motion to linear travel. Furthermore, unless you get a double ball nut or a ball nut with oversized balls loaded in it for your ballscrew, as well as angular contact end bearings for them ($$$), it’s possible to get worse backlash in a ballscrew than in a low cost anti-backlash ACME setup.
As to stepper motors of cnc router, these are proven technology that are easy to setup, and can offer truly impressive performance. If one has unlimited funds, then by all means, go with servo drives and planetary gearheads, and have fun tuning PID loops. It is fun — I used to do this for high speed pick and place robots. But for a beginner or anyone on a budget, steppers can offer an excellent performance/$ ratio, especially when coupled with a high end drive like the G540, and are quite easy to set up.
But in Redsail, you can find different types, ball screws, square linear guide ways, etc. We also have servo motor for our woodworking router.