I used to feed it in very small amounts primarily to mix with supplements. My horses loved it but I didn't feed enough of it to evaluate an impact as a major component of their diet.
I ended up switching to TC Lite because in one comparison chart I saw, it appeared to have even less of the dangerous carb/starch value (can't remember exactly the term they used) than the low starch. They love the Lite too.
I feed it to my Shivers/EPSM OTTB. I like it alright for him but he's retired so it is kind of hard to tell. It keeps him fat and happy, I can make it into a mash/soup easily if necessary. I did have my Training level eventer OTTB on it till he was competing fairly regularly and didn't seem to have a whole lot of sparkle. I switched him over to TC Training Formula and he quite literally came alive and bloomed.
The TC website is fantastic and can answer all your questions.
Proud and achy member of the Eventing Grannies clique.
If anyone lives in an area with Southern States, check out the Legends Performance pellets (not textured). Less carbs that the TC light and I believe also than the low startch. Protein slightly less that TC light (11 v 13%), but more fat (10 v 6%). I switched my two over to it-- mare was on TC complete and gelding was on a mixture of complete and light, as light alone wouldn't keep the weight on him. I was happy with how both look and acted with the switch.
i have asked on here if anyone found it ironic that the sr. has a lower nsc than the "low starch". my horse, a hard keeper, does well on l.s.- i add canola oil. my guy went nutso on the complete, so never have tried the sr. on him. a few horses that i care for do well on the sr., i just don't dare try it on my guy because of the experience w/ the complete. (that and the sr. smells like choc. chip cookies...makes me think "hmmm"- possible horsey-crack...)
I asked the TC rep about this very question -- the Lite has boosted levels of vits/minerals because the assumption is that you are feeding relatively small amounts. If you feed larger amounts, you may create problems overfeeding some of the supplemented vits and minerals...and so should feed Low Starch instead.
We feed Low Starch to our easy keepers during the colder months, when they get a bit more feed, and Lite during the warm months, when they get just a bit.
It doesn't seem to be particularly tasty, if I feed it straight, mine aren't all too enthusiastic either, that's why I add on cup of Senior and wet it all into a mash. One of the glucosamine supplements they are on has some caramel flavor to it, so all mixed up, they are gobbling it up.
But true the straight low starch pellet isn't the tastiest of them all.
My horse has been eating it for over a year now. No issues with her ever not wanting to eat it. She has great skin and shine. People comment on how great she looks and how steady she is. I don't feed a lot so I give additional supplements for minerals and vitamins.