The first difference you might notice between the two is the price. The jacket models are typically priced at double at what the horse collar designs are placed at. This is due in part because the jacket designs are a little bit more complicated, and often made out of superior materials such as neoprene. These types of materials used for the jacket designs sit more comfortably on the torso, and easy to take off and on without pulling anything up over your head, and are significantly warmer- which could be a great benefit if you are swimming in cooler waters. The horse collar slips up over your head and around your neck similar to that of a lifejacket that you might wear on a boat. It is significantly cheaper and doesn’t offer the same level of warmth as a jacket model. Plus, the horse collar type uses a strap that goes right between your legs to keep it from riding up to your chin while inflated. If that doesn’t appeal to your sensibilities- you might want to dish out the extra money for the jacket design.