I have been a bit reluctant to install the beta. Is it difficult to revert if too buggy?
It's very easy to revert, by most reports at least. (I haven't reverted myself since I'm very happy with the beta.) The installer download includes an uninstaller which, when run, reverts you to Safari 2 and all supporting system files required for Safari 2.
A few things:
• Make sure your Safari 2 application is in the Applications folder before you install and don't delete it or the Safari 3 beta application. (The installer and the uninstaller apparently need to see the application in place before they'll do their work.)
• I would uninstall any Safari hacks or add-ons that you might have before installing the Safari 3 beta.
• I would make sure to have a full system backup in the odd case that something goes horribly wrong. (I haven't had any problems, nor have most people, but it is a beta. And if something is corrupt or somehow wrong in your system files there is probably a chance of exacerbating that with the Safari beta install.)
• You might want to browse the Safari beta forums a bit first to see if any of its known bugs are things you can't live without.
Most hacks and Safari enhancer programs have updated versions now to work with Safari 3, so if you're using anything like that you might want to check for updates to any that you can't live without.