The automatic model is sensor controlled and has a lid which quickly opens when the trash bag gets about 10 inches and 130 degree angles from the can's sensor. With normal usage, the power will last about 6 months with 4 D-size batteries. For those that do not require trash bags, the inner bucket can be easily removed and cleaned when the trash is removed and taken out.
Outdoor trash bins with flaps are better at keeping the waste contained, even controlling smells to a certain degree. However, these receptacles are also more prone to getting broken or needing to be cleaned, since the flap comes into constant contact with the waste.