Hi Joe, I started collecting these after my grandfather gave me one of the original pearl 1906 Tuna Valley knives. It made for a perfect centerpiece to focus the collection around. You are correct, all my Tuna are collectible/display pieces, I don't use them.
The blades have a mostly uniform grind, maybe a few weren't perfect. Typical to fashion from Queen, the blades don't come razor sharp from the factory.
Most of my knives I acquired are 2nd hand, or bought at shows. In both cases you can pick up a knife for quite a bit less than full dealer price. I've spoken to Ryan and Courtney Daniels on many occasions (and bought knives from them), and they introduced me to some of the dealers, so I can also buy from dealer sites with a discount price occasionally.
I love the mammoth ivory, and all the Tuna knives I've seen have premium ivory. So much character and each knife has perfectly matched handles. And there is a lot of variety from knife to knife, so lots of different colors to choose from (white, brown, red, blue, green). Part of the reason that the mammoth handled knives are more money isn't just the ivory, but also the ivory is fluted on the ends, and then the bolsters are each hand engraved by Oiseau Metal Arts, so that adds to the cost, and they are also limited to only 25 pieces. At knife shows, you can often find an ivory Tuna Valley knife in the $350-$400 range, but even still, you are correct that most won't pay that much for a factory made knife. I've never found a flaw with any of the ivory handled knives, and I would say they are higher quality than factory made, but not quite up to custom made quality. But I like them, I'm blessed to be able to buy them when I wish, so I keep buying them.
Here is a newer one that I just recently got pictures of. The carpenter whittler in ivory.