I realize that half of AT here is like fuck Facebook, but it could be that a good chunk of the population here is older and wasn't in college when it first started. Or it could be that I'm Asian and I swear that the adoption rate amongst Asians is huge.
Moving on, the Facebook app is trash but I think we finally have parity in the past few months after the new interface was rolled out for Android.
But remember, it took til like December 2010 or something for Facebook to get push notifications on Android, and we're still waiting for a tablet version. I realize Facebook for iPad took a while to develop, but if anything apps for Android tablets are just.... horrendous. Twitter? Facebook? Nothing. It's great Android is finally getting Flipboard, but ask any iOS user who has an iPhone and iPad. The iPhone version isn't interesting at all once you've used the iPad one. Yet we see so much excitement for the Android one. As someone who had an iPad, I barely care about having Flipboard on my phone.
I feel like apps still get priority treatment on iOS. Even though they try, small new features roll out first on iOS. Foursquare for example rolled out its new interface across the board, but small changes they've made in the past few months have always been iOS first.