Sibes are extremely independent dogs, so yes, definitely different from a GSD or a Golden. They don't give a hoot what you think or what you want them to do! They have their own mind, and the scary part is - they know how to use it! If they don't want to be in their crate, they'll figure a way out of it. They might scream for a bit, but when they get quiet...they are planning escape. If they don't want to eat, they won't. Extremely picky, and you can't wait them out. Stubborn, stubborn, intelligent an independent breed. Mentally AND physically, they are extremely demanding dogs not for the faint of heart. Usually around 10-16 weeks and they are getting dumped at shelters. The majority of the public can't handle them. They really make terrible pets for general owners.
Most pups will become packbound if they are raised together, though, that isn't just a Sibe thing. And especially, two dogs of the same litter are never recommended to stay together. The dogs bond to each other instead of the humans, or in siblings, they usually end up fighting.