The type of feature depends on the type of riding you want to do. For example, I'm interested in freeriding so I want a binding that is stiff and will respond to my movements with less effort. A terrain park rider would prefer more forgiving bindings to accommodate landings and such.
Once you go down that path, there is more than enough information on the web to answer all of your questions, you'll probably become overwhelmed. I like to youtube bindings and listen to people give reviews.