Here is the (my) logic from my corner of the world: Commercial gut loads for feeder insects are mostly bran, grass, and grain based. When you look at the ingredients, you will find an absence of many nutrient rich food sources. Look up Sandra Chameleon on the Forum and open her blogs on gut loads, she will open your understanding of using a variety of food sources for your feeder insects.
If you want to see the product list on Cricket Crack, Bug Buffet, and Super Chow, look at my ad in the classifieds under "Chameleon Supplies" titled "Gut Loads and Feeder Insect Supplies," and you will see the quality of those 3 products.
You can make your own dry gut loads and wet gut loads, but Rapashy Bug Burger and these dry gut loads are the standard I would use to look at any commercial gut loads, or making my own.
If you make your own dry gut load, grinding ingredients fine enough is absolutely necessary, and I have had the opportunity to buy 2 blenders...so far!
CHEERS!
Nick