The chief advantage of an iBook is its availability even when you are not wired to the internet or do not have wireless service. The Government's Contingency Contracting Corps who travel to disaster areas around the world to lead emergency response and rescue missions can now have FAR at their fingertips (assuming that they at least have a power source for charging their devices). Besides these "first responders", some agencies have employees in remote areas that do not have access to the internet. The Agriculture Department for example has many such employees.
The FAR iBook has the same functionality that is built into every iBook. Readers can perform searches, write notes, and highlight or save the sections they use most often.
Regulations change quite often so how will the FAR maintain it currency, once installed? iBook owners will receive a notification each time there's an update and new editions will automatically download the next time the particular device connects to the Internet.
The FAR iBook is free and can be downloaded here.
By the way, FAR has, for many years, been available as a .PDF file. It's huge and difficult to search or navigate but its also free and doesn't require "iBooks" to use. Download the .PDF file here.