From The Omni Group:
OmniWeb is a full-featured native web browser for Mac OS X. Highly multi-threaded and written using Apple's Cocoa frameworks, OmniWeb is designed to provide you with the best user experience you'll find in a web browser. We think it's important to polish every user interaction to make sure that the browser acts the way you want it to--so you can stop thinking about the application you're using and just get at the information you want, quickly. (If you don't like anything about OmniWeb's user experience, please let us know!)
What's new in this version:
OmniWeb is now signed with Developer ID so it works well with Gatekeeper on Mountain Lion.