Being a web developer, i find Firefox to be more comfortable than Chrome.
The features i like in Firefox more are the Error Console, Firebug and Web Developer extension.
Web developers often find a need to check the request - response status in their web applications and the Console window of Firebug extension in Firefox makes our life simple. Also the firebug is pretty useful and easy to launch from the status bar in Firefox.
I used to believe that if a site ran successfully in Firefox, it would run smoothly in any other modern browser (IE6 is an exception though).