1. Stir rod improperly bent causing kernels to become stuck. Owner had to correct in his shop.
2. Vent holes in top too large allowing kernels to spill out from the top during popping cycle. 
3. Cooking surface reduced from previous versions not allowing adequate room for the stirring action because the popcorn depth is too deep for proper heat distribution.
4. Wattage too low to adequately heat the oil quickly leaving many kernels unpopped.
5. Internal thermostat cycles on and off causing the unit to go through two to three popping cycles for each one cup of medium size popcorn.
6. Functioned inadequately since shortly after the initial warranty expired and now has become worthless.