How should clay versus cast-iron cookware be evaluated when buying a rotating clay-pot cooker?

When choosing a rotary claypot rice cooker, do not size the pot opening alone, because clay and cast iron behave very differently. Clay heats gently and holds heat well but cracks under sudden temperature swings; cast iron responds fast and stores more heat, yet its weight can bend the cradle or stall rotation if support is poor. Have the supplier run three consecutive batches with both pots you intend to use, logging the heating curve, base heat evenness, crust and rice-crisp formation, plus any cracking or cradle deformation after thermal shock. Verify actual pot weight and how it seats in the cradle rather than trusting quoted capacity. Keep these trial records with the machine file for future pot changes or flame adjustments.