Camino is a native Mac application, so it looks better (in most people's opinion), integrates with the system better, etc... however it doesn't use XUL, so it doesn't support firefox extensions.
And Camino, being fully native, can't use the XUL extensions, which many find a benefit of Firefox. And also, a benefit for Camino. If I want FF extensions, I use Firefox. On the other side of the ...