Natural balance has good quality ingredients, but the meat content isn't nearly as high as Orijen, and is therefore less calorie dense. Like some of the other brands of high-end kibble, Orijen has a very high calorie density (483 kCal/cup).
Before I got my dog, I put together a spreadsheet comparing the calorie density of different brands in order to calculate the true cost of feeding. Orijen, Innova, Innova EVO, Go! Natural, Timber Wolf, and Canidae Grain-Free had the highest calorie densities. All (except Canidae) were a bit more expensive based strictly on weight, but you also go through each one a lot slower due to their density.
Orijen actually has the lowest calorie density of these brands, and Go! Natural had the highest. Canidae ended up with the best value of in terms of calories/dollar. After trying out some samples with my dog (you can order free samples online from
K9 Cuisine, I finally settled on the EVO.