Not quite true. The TCP stack (the thing that actually connects you to the internet) is much cleaner under *nix. Microsoft has come some distance, but the *nix implementations are simply better. There are also multi-tasking reasons why the *nix version of the browser will perform better than the windows equivalent. That said, I agree that opera for example is going to blow the drawers off IE or netscape on either platform. The main reason you'd want to move off IE/windows is virus protection, plain and simple. Microsoft until recently just didn't care about security. Their implementations show it (The way the read mail is an example of how not to be secure.)