When selecting a CNC Trainer, you must prioritize the control system compatibility, as it should ideally mirror industry standards like FANUC, Siemens, or Mitsubishi to ensure transferable skills. Key mechanical specs include the positioning accuracy (typically ±0.01mm or better), spindle speed range, and the rigidity of the machine bed (cast iron is preferred over aluminum for vibration dampening). Additionally, ensure the trainer supports G-code and M-code programming and includes a simulation software suite for offline practice.