Probably the best thing is to install both and test drive them out to see what you personally feel more comfortable with.
Chrome is also worth trying out. If you’re worried about security, in a recent hacking competition using Internet Explorer, Safari, Chrome and Firefox, Chrome turned out to be the most secure and the only browser tested to resist being exploited. In a PC World speed test, Chrome also turned out to be the quickest of these 4. Unfortunately, both the hacking competition and speed test did not include Opera.
Personally, I prefer Firefox on both my PC (running Windows XP) and portable Asus EEE (running PCLinuxOS). It seems to have everything I need, including Ad-block plus, development tools and Firebug and would find myself lost without these. For my Mobile phone (Nokia 6300), I use Opera Mini (java app.), as it does a great job at rendering websites for its small 240x320 resolution screen and is far quicker at loading pages than the phone’s built-in web browser.