When evaluating JMGs, the motor wattage is the most critical factor; for heavy-duty or commercial use, a motor of 750W to 1000W is recommended, while 500W-600W suffices for standard residential use. Ensure the motor uses 100% copper winding for better heat resistance and longevity compared to aluminum. Additionally, check the RPM (Revolutions Per Minute), which should ideally range between 18,000 to 22,000 RPM for efficient grinding. The quality of blades is equally vital; prioritize 304-grade stainless steel blades for corrosion resistance and sharpness retention.