Question says it all
Corviknight might be slightly better because it has better typing but again terastalizing exists. You will not outspeed a lot of things with either of them but if you need a bulky Pokemon then Corviknight would be better because it has bulk up and roost. Corviknight also has power trip. Kingambit is better offensively with Kowtow Cleave and its ability Supreme Overlord. You also have sucker punch (which is unfortunately an egg move) and iron head. Kingambit has defiant too but It's really up to you.