WWWOFFLE has more features than can be described here. It will censor banner ads, clean your HTML, decorate it with random colours, schedule fetches for off-peak hours.
Unfortunately, the HTTP traffic that WWWOFFLE generates is disgusting. It will open a connection for every fetch, and forces the client to do the same.
WWWOFFLE only caches complete instances.
I used WWWOFFLE for many years, and frustration with WWWOFFLE's limitations was the main reason why I started Polipo in the first place.