Facebook tried to pull a "Windows Metro" move and failed miserably.
The hardware itself is decent for an average phone (still beats the iPhone, LOL), but instead of making the FB Launcher an option that users could launch, they slapped it in front of the well-known Android JB interface. People walk in the store, press the button, see some unfamiliar/weird stuff and move on.
Besides, what kind of launcher is that, it works only with a handful of phones? Really?
TBH, if the BF Android app was any indication, this flop was expected. There are no Android coders at FB.