Even though Arabs are my favorites, I personally love Mustangs. A horse is a horse, so people that think Mustangs shouldn't be tamed and trained are just ignorant. The age to start one kind of varies on the horse and when you got it. TraIning should start right away, but I wouldn't start it under saddle until it's two at least. Some people recommend three, but it really depends on the build and physical maturity of the horse. Mustangs are good for any discipline, but from what I've observed, anyway, they seem to be better at Wetsern disciplines. Quarter Horses tend to own barrels, but Mustangs rock it, too, and I'm determined to try it with my Arab ^_^ They seem to make great ranch horses and Western show horses, but I think they could do any discipline.