If you own a horse, stick with what it was trained for. If your horse has not been saddle trained yet, your best bet it to visit a better riding stable and try what they have. There are a lot of variations of the western saddle, some of which are best for specific work. But, they are generally designed for comfort on long rides.
Endurance saddles are good for long rides, but usually don't hold up well.
English hunt seat saddles are reasonably comfortable if you like the riding poition and are designed for all sorts of torturous riding in the course of chasing foxes.