I'm not a fan of the look of appaloosas and, as a hunter, I would never actively seek one out to buy, but I have had some great experiences with them.
My first show pony was an appaloosa and one of the ugliest ones I've ever seen: short neck, visible sclera, blue roaned, spotty thing, with no tail and a mohawk. He was a nasty little thing too, pinned his ears back whenever anyone walked near his stall and he needed a muzzle, but he was the best pony I've ever ridden! Smart, responsive, and honest. He could turn on a dime and had great form over jumps.
I would never write them off as a breed, all the ones I've known have been quirky, but wonderful and super intelligent.