A belt machine need calibration if temperature change and over operation time (belt tension changes).
If no position feed back system used the precision of this kind machines is ok for >=0.5mm pin pitch and down to 0402 placement.

Another point if you use round rail linear guides you receive additional vibrations and head shaking because structure is not as strong as profile rail linear guide systems we use.
Profile rail linear guide systems have more rigidity and precision.

The ball screw machine need only single time calibration and position is stable over long time. Our HIWIN ball screws receive +/-0.03mm precision over 300mm distance.
Over all precision for our HP machines is about +/-0.05mm.

The placement speed for belt and ball screw machine is equal because it depend on physical limits. You can't use higher speed without loosing precision.

VP2000S / VP2500D
- Round rail guides
- Belt machine need slower acceleration and break curve because belt is working like a spring when head stops.
- The head shaking when movement stops will decrease precision or you need to use slow Z axis speed.
- belt tension changes over time and temperature changes and will influence the final position
- Placement precision good from 0603 to 20x20mm >=0.65mm pin pitch


VP-2500DP / VP-2500DP-CL16 / VP-2500DP-CL32
- Profile rail linear guide system from HIWIN
- Belt machine has closed loop stepper driver but belt tension will influence the final position so we don't have absolute position.
- belt tension changes over time and temperature changes and will influence the final position
- Placement precision good from 0402 to 24x24mm >=0.5mm pin pitch


VP-2500HP / VP-2800HP / VP-2800HP-CL22 / VP-2500HP-CL32 / VP-2800HP-CL64-4H / VP-2800HP-CL62-2H
- Ball screw spindle (HIWIN)
- Profile rail linear guide system from HIWIN
- Machine has no head shaking because immediately stops on position only the servo motor regulation may need a short time to stabilize.
- Machine uses encoder AC servo motors and are mounted directly to the spindle. We receive absolute position at high precision.
- Placement precision good from 0201 to 30x30mm >=0.40mm pin pitch

Finally the combination of profile rail linear guide systems plus ball screw spindles using AC servo motor drive with encoders receive the best precision. >> HP machine
For Z axis precision we use a linear belt drive instead of a simple spring and rocker arm system.