Entirely agreed. My pet whinge about Firefox has always been that it's not a real Mac application and that it simply caters to the lowest common denominator, i.e. Windows. I'm not bothered that much about the appearance of the browser but what irks me is that it doesn't support those features than any good Mac (i.e. Cocoa) application does, such as using the network settings set in System Preferences, storing passwords in Keychain and checking my spelling using the Dictionary that I've already configured. As a mobile user it drives me bonkers that I have to change my network settings directly within the browser whereas all my other applications don't need to be touched in order to work within a different network.

Inter-operability is marvellous but it needs to be done right for the target platforms and not just for the lowest common denominator.