If I joined a company now without HUMS I'd ask the chief engineer why he hasn't got it. If he was then indifferent about it, I would have great pleasure in approaching the board and then instigating it.
Where I've worked, it's saved a few guys catastrophic engine failures , and even gearbox early warnings. It'll also check tail rotor problems and make you tea in the morning.
DO NOT BUY A HELICOPTER WITHOUT IT!