The design of the saddle, the fit of the saddle, and the skill of the rider interact in ways that are extremely complicated. If you add in the asymmetries of the rider and the asymmetries of the horse, you are talking about a group of interactions that are even more complicated. It is no wonder that a particular rider and a particular horse can achieve success with a particular brand of saddle, when that same brand of saddle can make another rider very uncomfortable and another horse very soar.
I have declined to carry any brand of saddle that has a longitudinally flexible tree. These trees have the potential to offer a better fit for the horse and better feel for the rider, but if they allow the bouncing of the rider to deform the shape of the tree every stride, they will cause friction and bruising on the horse. Don’t be surprised that the most talented dressage riders can use these saddles and swear by them. Those riders have the strength and coordination to distribute their body weight down the length of their thigh. They do not bounce in the saddle, and they do not jam their weight in their stirrups. Unless the rider has these skills, the saddles will cause discomfort for the horse. These saddles have there place in the dressage world, I suppose, but I do not want to sell them. For jumping, almost everyone agrees, a longitudinally rigid tree is required.
Happy Back Riding offers saddles with rigid saddle trees, Lovatt & Ricketts and Santa Cruz. And we offer the WOW saddle. A saddle with a tree that is longitudinally rigid and laterally flexible.