Q. What’s the difference between Camino and Firefox?
A. Camino is a native Mac OS X application; this means it will only work on the Mac platform. Firefox, however, comes in all kinds and flavors and works on several operating systems. Camino combines the Mac user experience — famous for its consistent visual and behavioral experience across applications and the operating system — with the Gecko rendering engine — built and tested by thousands of volunteers, incorporating the absolute cutting edge in web innovations. Camino uses the Mac OS X Aqua interface and uses APIs and services only available to applications native to Mac OS X. Some of these services include the Address Book, Keychain, and Bonjour (Rendezvous). Though Firefox looks like it is using the same Aqua interface, it actually fakes it, and Firefox focuses on cross-platform consistency rather than integration with Mac OS X technologies.
http://www.caminobrowser.org/support/faq/#about_camffdif