What are the differences between a freewheel and a cassette hub in terms of functionality and performance?

A freewheel and a cassette hub are both components of a bicycle's rear wheel that allow for coasting. The main difference is that a freewheel is a single unit that includes the ratcheting mechanism, while a cassette hub has separate cogs that can be replaced individually. This makes cassette hubs more versatile and easier to maintain. In terms of performance, cassette hubs generally provide smoother and more efficient shifting compared to freewheels.