I give Firefox OS three eyerolls...
It doesn't seem to offer anything different or unique that isn't already out there or can't be covered by a skinned/modified version of android. Firefox OS looks more like Nokia's old Symbian OS than anything. Just another app centric OS with circular icons....
I'd rather see the Ubuntu Phone come to fruition as it looks like it has better potential as being a new kind of OS, even though that is also an app centric OS.
And by what I mean by "app centric" is that the OS itself can't do anything more than a web browser, text, and calling. You HAVE TO HAVE an app for facebook, app for twitter, app for youtube, app for amazon, app for EVERYTHING. And there isn't much that the OS already does or make relevant information easier to view.
The ONLY real new and innovative/non-time wasting OS I've come across so far is Windows Phone. I find myself trying to find something on my phone to kill time because all the information I need to know is usually on a live tile, sometimes I'll open an app for further info as the live tile will lead me there versus just having to go app to app to do something or view something. That, along with the lock screen. I will laugh at the smartwatch if it develops, and all it will do is basically the lock screen of Windows Phone on your wrist as the other platforms will probably rely on an external device to make information quicker to view.