Needing some extra oomph in my internet usage at home (w. satellite internet), I downloaded Opera. Basically, my impression is that Opera 10 (w. Turbo enabled) checks an Opera server for compressed images (where most bandwidth, I suppose, is used nowadays).
What actually impresses me the most w. Opera 10 is the use of a small piece of desktop real estate at the top. Opera then puts small images of each screen at the top so you can see what is loaded on the other pages.
The jury is still out on how much faster websites load.