I don't know about that particular engine, but industrial and diesels have a better track record than automotive of parts longivity.
But this rarity to me doesn't make it "desirable." Those aren't factory turbo'd and aren't all that much on power. Those are only 4 liter rated at a little over a hundred hp. A slant would probably run circles around 'em for power, and of course their "rarity" speaks for itself---there's a good reason not many are around............