I remember one spyware that redirected traffic from Google, Yahoo, and MSN to their engine. It was on my friends computer, but I don't remember the site because it was a while back.
I think I hate RedZee the most (it is weird that you get two different interfaces if you type redzee.net or if you type redzee.com). Maybe I don;t hate the engine as much as I hate the company. They list a link to their new commercial, that by the way has be new for the last 3 years and they sell SPAM traffic to unknowing individuals through hard sell tactics. Overall, they are a crummy organization and that makes me hate them, and thus their engine.
be careful when downloading a free software, sometimes it require also to install a toolbar of unknown search engine with full spyware