I don't remember if it was Phandroid or Android Central, but one of them posted a way to improve android facebook notifications. Basically the fix was to log into your facebook account from a blackberry and then log out (anyone's blackberry; it doesn't have to be yours). Once you do that, Facebook for Blackberry will be an authorized application within facebook your facebook account and you'll start getting notifications sent to your android app. (you can check by going to privacy settings --> edit application settings from a PC.)
I came over to android from blackberry so I didn't specifically try this, but I will say that facebook for blackberry is an authorized app on my facebook account and I DO get notifications.