A new feature allows you to randomly change images on your idle screen. You can specify the album or customize the sources (form Facebook like 'Photos of you') from where the images need to be picked up. The whole GUI looks much better than before and it is much easier to use now. There is also a feature that lets you refresh your feeds by shaking the phone. In case you wish to refresh with shaking, simply pull down the feeds page at the initial position and leave it.
This WP8 Facebook application happens to be the best version that is available currently if compared with iOS or Android. Do visit the Windows Phone Store and install this free application which indeed makes WP8 worth a shot.
Download Facebook for Windows Phone 8
Download Facebook for Windows Phone 8