They're very easy to breed, however raising depends on where you are. In colder climates, they require TLC through heat lamps, etc. Though who knows, they may make it. Out where I am, temps rarely exceed 75 degrees, and in the winter are always around 35-45. It doesn't get freezing too often, and my Shamos are out 24/7 in whatever nature gives them. . . But I do have some heatlamps in their coop.
With their slow growth, they require certain things like enough room to roam so their bones and legs grow properly, broad perches to prevent bent breastbone issues, and slow set perches to prevent fractures. They get leggy, and they don't stop growing well beyond 8 months, so there's a decent amount of care that goes into them, like any other large breed.
Otherwise, they're very good foragers, they're pretty broody and not only make good mothers but also flock protectors, and they're great vermin control too!
My only pair for the moment follow me around all over the place, the stag especially. I don't think I've known a more friendly, intelligent, and calm breed. But, one thing is certain - Do not have males together. Even if you've got a young stag and a larger, older breed with spurs beyond an inch long. . . . The one to worry about is the larger rooster.
I think everything is a pro, except the inability to keep males together (which to many, doesn't matter) and the care they need, which is needed for any large breed, really. To my very limited experience, they also make good meat projects when crossed with more "normal" postured breeds, especially large ones. Despite their skinny appearance, Shamos are very well muscled, and feel like a brick. Even as a young 2 week old chick, they feel like little rocks compared to other chicks. Put a little more horizontal stature and general compact size in there, and you've got a very Cornish-looking bird.