They are very comfy and ride very nicely balanced. You notice the hole for maybe your first trip around the ring, and then you don't. I like it when I tried it, but it wasn't the right saddle for my guy. Leather quality is on par with the much higher end French saddles, so they are lovely looking and very sticky.
A lady at my barn has one and loves it. I inquired about those saddles, but they didn't have a used one with the specs I was looking for. They are nice saddles, but definitely more popular with the eventing crowd. I believe they debuted at Rolex 2010.
This just looks a lot like the old Army Cavalry McClellan design.
Those were purportedly ultra comfy for the horses but not so much the riders. I think they were trying to alleviate pressure on the spine since riders spent such long hours mounted. I wonder if Dutton was inspired by the McClellans?