stepper acuracy

Hello Group,
I am a newbie and would first like to say hello and wish everyone a
happy new year..Now for the question.I am thinking of buying a
converted mill\drill from cnc masters the "cnc jr".This machine comes
with ball screws-x-y- and anti backlash on -z- 1000 oz\lb
steppers.What I am wondering is will a machine of this construction
be sufficiently accurate and fast enough to cut detailed geometry
such as a mold?Are servos the only way??Any advise would be fantastic
and appreciated.
Greg