There are some interesting parallels to the Windows Phone UI here. As I understand it (and I don't own a Windows Phone), Microsoft's intent was to provide a UX that is more social and tied to user tasks rather than apps. Facebook Home looks like they use a similar underlying concept, with a stronger focus on social interactions rather than user tasks. Apps are still there, but are not the main focus.
I rarely use the Facebook app on my phone, so I'm not their target audience. However, I've seen a fair number of teens and young adults absorbed in the Facebook app on their Android phones (yup, Android, more than iPhones, because they're cheaper). So it will really be interesting to see if that audience takes to Facebook Home too.