The only thing of any use to me for a Facebook app would be notifications and alerts. So, I'm good just using the Facebook iPhone app for the 'limited' notification alerts and then use Safari to go to the native Facebook website.
However, does anyone know of an app that provides notifications when Friends post status updates to their Facebook walls? So far, it seems that both the Android and iPhone Facebook Apps do not support this. So, I am relying on the integrated HTC Sense on my Android phone which syncs my friends update status and display's those updates to me in the People App, but it doesn't alert me at all with any notifications if a friend updates their status.