radiantmark said:FF is totally different. If you think FF is mac-like then you don't understand the difference between cocoa apps and non cocoa apps. It looks/feels nothing like mail or any other cocoa app. It tries to and probably passes like a native mac app to most users, but not to people have a feel for cocoa apps.
Carbon applications are native applications, just as Cocoa applications are native applications. You'd be surprised how many people think that certain Apple applications are written using Cocoa when they're not. It's not as easy to make mistakes while developing Cocoa applications, but you can make mistakes and they often perform poorly because of late binding--Cocoa is not the holy grail.
Firefox, and the other Mozilla applications, are fine native applications on Mac OS X even though they are also running on other platforms, too.