I use this popper a lot for family & friends
I have had rhis popper for 30 yearsinfairly steady use. Unpopped kernels depends on the quality purchased. I use Orville's and only had one unpopped kernel today, not si with stire brands. When I want butter, I don't use the cup (inadequate), but melt a teaspoonful (mostly 2) in the microwave (1400 watts) for about 30 seconds. Usually, I use nobutter or salt.
Popnpopper
Calgary Canada