There has been an official Facebook App on Windows Phone for quite some time now but there have been lots of complaints about its performance and functionality.
It seems someone has been listening to the concerns because an update was published to the app that makes some improvements at least for Windows Phone 8 users.
According to the listing those updates include:
New for WP8: Improved performance, support for multiple resolutions and tile sizes plus more!
I am not sure what the plus more part is and still need to poke around the app to see but I can say the performance side on WP8 is much improved. The app now opens quickly compared to my previous experience with the older version.
The other area specific mentioned in the <sarcasm>detailed release notes</sarcasm> is the addition of multiple tile sizes and live tile features. As you can see below the wide tile rotates between your latest update and your Facebook profile Cover Photo. The medium tile size flips between your latest Facebook update and the app icon.
It does seem to only show Status Updates as opposed to also showing Timeline entries, updates and posted images. That would be a perfect setup for this Live Tile so hopefully it will be in the next update.