He's registered APHA. He does always throw color but it's not always the leopard. Some have blankets. He would be a good stallion to breed to if your mare is too big and heavy. A refining stallion. Also, if your looking for a sporthorse for jumping, hunter. He does have very good movement too, so he might make a nice eventer prospect. He has an outstanding temperment. I would not use him if your looking for an FEI level dressage prospect.
I do believe he could be approved for breeding with the AWA, American Warmblood Association.
While he is a nice looking horse, you wouldn't get as many people interested as if he were solid color. At least for hunter prospects. Though there are more and more going into the ring, they just don't place as well because they don't "fit the picture".
Are you looking to buy this stud or breed to him? Either way, has he been shown? Has he done anything other than breed?
He might be a little too different for the hunter ring, as many people prefer solid colors. I've only actually seen maybe... four different appaloosas in the ring (maybe that's just me). I have no doubt that he has the talent, but his color just doesn't seem to be in demand.