After a 6 month wait, the official iOS app for the Battlefield Battlelog is finally here. The app is fairly complete with just about everything you need. The one thing that it doesn't have which I feel is very important is the ability to see every single weapon's profile and what unlocks are next for that specific weapon. It probably took them so long because they had to work on all the massive mistakes the game launched with.
The app features a ton of useful things like keeping track of your overall stats and how many kills you have with each weapon. You can also keep track of your next upcoming unlock. There are better apps if you are just looking for stats. The app called BF3 Stats lets you keep track of individual weapons and their stats.
As of press time there is no release date for the Android version of the App.