Our pets were all in the cargo hold of the plane from Tokyo and the Captain came to talk to us about the temperature in the cargo hold as he wanted to be sure it was right for the parrot as well as the dogs. They arrived here perfectly fine. It is better for the pets that the hold is dark as the pets sleep. They don't hear humans talking, smell food being served, etc.

I don't know what "horror stories" you are referring to. I have worked with many pet shippers over the years and not once has this been my experience.

Many animals travel better in the cargo hold than in the cabin as they don't have nervous owner fussing over them, plus in the cargo hold they can have a larger, sturdier and roomier kennel fitted with a water bottle, which is essential for a long flight to avoid dehydration. How does one affix a water bottle to a carry bag? The extra space in first class doesn't change anything from my perspective.

I once sat next to a passenger with a dog that whined most of the flight. It was awful. In first class, if your dog does anything but sleep, you are going to annoy others who opted to be in first class for a reason.

If you are travelling with your dog, you don't need to use the services of a pet shipper. My pet shipper always recommends pets travel with the owner (though not necessarily in the cabin). This keeps the costs down.