Servo = accuracy, precision, consistency, and speed
Stepper = cheap
Which do you need?
All modern, commercial grade, metalworking CNC equipement uses servos. It's like the old adage about IBM and job retention. "Nobody ever lost their job because they specified or recommended IBM hardware." Plenty lost their jobs because they didn't.
Fred Smith - IMService
http://www.imsrv.com
Inexpensive servo solutions for desktop machines