Well, I'm very much a Souveran fan. Most people, including myself, make the comparison that products like S100, Trade Secret, Natty's and several other fine carnauba's give 90 to 95% the look of Souveran on dark paints. So, you have to decide if the extra money might be worth the 5 to 10% increase that you might achieve.
Having said that, I would recommend that every detailing enthusiast try at least one jar of Souveran. There is really something special about Souveran on dark colored paints.