Firefox 31 hit the Arch repos at some point today and now I have it. Since Mozilla moved to their 42 day release cycle, most of the changes from one release to the next have been incremental and not really worth noting. But I did notice something new when I opened a new tab.
That search bar immediately above my most recently used tabs is new. And handy.
And, for the borg-averse, you can change your default search engine by clicking on the logo. This gives you a drop-down showing your currently installed search engines and an option to manage the same.