I dont feed it and have no direct experience but I dont understand the need to keep ingredients secret. I'm not a human nutritionist but I like to know what's in my food, I'm not one of these who wont eat x or y but especially if I'm buying convenience food I like to know the basics in it. If I picked something up to buy without that info I wouldn't buy it. Same with dog food, and I'd take the same approach with horse food.
I dont need to understand all the micronutrients but there are certain red flags for me - sugar and/or fillers being listed high on the ingredients is a big one, I know enough to know that!
My knowledge or understanding is irrelevant though, these days all we really need is available on the internet. I've had some super conversations with experts from other brands who respect my equine knowledge and arent trying to blind me with science, belittle me, or hide anything. On that basis alone I'll stick with them.