Lunascape is one of a kind of web browser and it very unique because it has not one but three rendering engines. The latest Alpha version of Lunascape supports three of the most popular rendering engines used in other web browsers, including Internet Explorer, Firefox, Safari, and Google Chrome.
Upon setup, you can select your default rendering engine. Gecko or WebKit are known for their blazing fast performance when loading many web pages and web apps,. Or you can choose Trident if you frequently visit web pages that only work with Internet Explorer.
The browser has a built in screen capture utility, skins, and has a full screen mode. It supports bookmarklets and add-ons, but right now there aren’t a ton of Plugins available. Unfortunately it will not work with Plugins designed for Firefox, Safari, or Internet Explorer.

This browser would be useful for developers who have to test there web pages for compatibility between different browsers. But be warned this is in Alpha stage and has some serious bugs.

You can get Lunascape here.