Browsers have nothing whatever to do with SEO. What you have for breakfast has a greater influence over SEO than which browser you use.
The more plugins you need to add to a browser to get it to work properly the poorer the browser is in the firsat place. Firefox is the only browser that doesn't have a full debugger built into the browser itself. Both Firefox and Chrome require the use of plugins of some sort to implement many features built into the much smaller and much faster running Opera browser.