It isn't really a true comparison in that Onspeed, as I understand it, compresses pages that you request while surfing to make them download faster.
So you access the web through their server(s) and there will be a speed improvement as long as the pages you request can be compressed enough to make the extra time worthwhile. In certain circumstances their will be no improvement and things could take longer!
Onspeed can speed up dial-up but it really isn't broadband.
click here for a review.