After months of beta testing, Mozilla makes Firefox for iOS official
But why didn't Mozilla release Firefox on iOS long ago? Backstory time: Apple won't approve a third-party browser to the App Store if the latter does not use Apple's own WebKit engine. Unfortunately for Mozilla, Firefox relies on its in-house Gecko engine, which is equal to a "no-no" from Apple. So, the developer was on the fence with two options before itself: either fully embrace WebKit or stay away from the App Store.
It seems that the former option has been chosen to be more beneficial, and lo and behold, Firefox is now openly available for just anyone with an iOS device to give it a spin. Well, you still need to have iOS 8.2 or newer on your device, but judging by the adoption rates for Apple's mobile gadgets, that shouldn't be a problem. Additionally, the browser is optimized for the recently-launched iPad Pro from the get-go.
Feature-wise, Firefox for iOS has a large arsenal of features. Private browsing, Firefox Sync, and "visual tabs" are just a few highlights that could be found in the feature list of Mozilla's spic-'n-span iOS browser. Of course, it's free to download and use, so don't hesitate to give it a try.