I'm going to quote Tony Athens at Seaboard Marine on this, keeping in mind that he does not sell CATs- they are his competitors. He does, however, have an excellent rep for honesty and maintains several boats equipped with CATs.
He feels that they have a higher problem rate than Cummins or Yanmar. He pointed out that there are satisfied CAT owners out there and, indeed, when I put my very well maintained 3116s up for sale I had dozens of calls from all over the world, and ended up selling them to the Caymans. But the fact is, I took out engines with a total of 750 hours on them, running fine, to put in something else. My friend Dave has had several catastrophic failures with similar engines. His boat has two new engines. Mine is getting repowered.
I can't imagine a situation in which I would willingly accept CATs in a new boat. If the manufacturer insisted on them, it would be a deal-breaker. That's all there is to it. I'd go elsewhere.
The choice of which brand of marine engines goes into a new vessel is dictated by a lot of concerns, and frankly I think that which is the best engine for the vessel sometimes gets left back on the drawing board. I think far more important is what sort of deal the boat builder can get from the engine company, especially if they are willing to set it up so that their entire line is powered by one make. Right now, AFAIK, all Hatteras yachts are powered by either CAT or DD/MTU. Do they offer anything else? Do they even offer DD/MTU any more?
I have heard of at least one boat builder (Viking Yachts) who were sustained through lean times a while back by the fact that MAN was willing to extend them engines and gears etc so they could continue to build and sell boats. How true this is, I don't know, but I don't dismiss it out of hand. The single most expensive piece of hardware that goes in any powerboat is those engines and drive train. Haveing someone front that to you would be a powerful incentive to make them your main supplier.
I just don't think CATs quality control in marine engines is very good. I know they build good truck engines and earthmoving equipment. They've been in business for decades. And maybe their marine products are better. But I only have one boat, I am not (thank God) a fleet admiral, and I didn't have enough confidence in them. In fairness, my friends at T&S Marine in Crisfield have sold hundreds of CAT engines to watermen who have to make their living with them. However.......
...last year T&S picked up Cummins also, as a new engine dealer.
Oh, and I don't think much of Volvo either, but again, I've never owned one. Look on the
www.boatdiesel.com forum, and you'll see lots of opinions on everything.
... have you sea trialed the boat ? 
