I only know of it what I've seen on the site link you provided, but it seems that it's all predominantly grain & molasses(with mineral mix that looks OK), and corn features highest in most of the products. As such, I wouldn't want my horses eating it. If I kept my horses at a place that fed it, I'd buy my own feed.
Horses don't tend to cope well with high starch/sugar diets, and it causes a range of problems, including IR & lami. Oats are about the safest grain for horses & corn is by far the worst, according to my equine nutritionist. I am a hoofcare practitioner, unfortunately very familiar with some of the outcome of this.
As a rule I would not feed grain or molasses/sugar to horses. It is 'junk food'. Most horses, unless they are in hard work, don't need the extra energy anyway, and there are generally safer forms if they do. If grain/starch/sugar is to be fed, it is important to feed it little & often - very small feeds in at least 3-4 meals daily. This helps minimise the likelihood & severity of health problems and maximise the goodness the horse can get out of it.
**In saying all the above, it does depend how much they get & if for eg they only require a cup per day to balance nutrition(like a 'ration balancer') this is *generally* OK.
Of course, don't just go on opinion, but do your own research, and I suggest finding a good nutritionist or nutritional service(pref independent of feed co's) to consult. I personally sub to a great service called feedxl.com