Given the fact that most of the Dem leadership in WV is more socially conservative and pro-coal than the national party, I'd say Justice gets it. But I suspect it will be close no matter who wins. Keep in mind that until very recently, West Virginia was solidly blue at the state level, even when it was trending hard for the GOP in national elections.
I think Justice is more likely to win than Manchin.
Manchin isn't up until 2018. Either way, I think Manchin is pretty safe as long as he wants to run; he's much more moderate/conservative than the national party and has made a name for himself as a social conservative and defender of the coal industry.