Hog style harnesses are a single piece of webbing threaded through the backplate, and a crotch strap attached to the bottom. Comes with 5 d-rings - left and right shoulder, left hip and front and back of crotch strap. Also, the inflator hose is held by a bungee cord.
The deluxe ones are those with the padded straps, quick release systems, inflator hose keepers, etc.
I use hog style, because it's easy to pack, maintain, and relatively cheap! It's also more durable and simpler to don imo.