I use SmartPak with my Horses and Dogs.
They deliver my dog's heartworm preventitive every month so I don't have to worry about forgetting to give it to them (i know we have all done it in the past, LOL!). I had Dreamer on Smartpaks for a while, but since I don't board my horses (i own my own facility) I decided to buy the tubs of suppliments from them. And they will really ship ANYTHING at a flat rate of like 7 bucks or something like that. They also do custom products and embroidery.
As our facility expands, I might choose to put my own horses back on Smart Paks just incase a boarder tries to get "free samples" of my suppliments.
Oh! And this was great too... my vet perscribed me 50 grams of bute (50 tablets). I went to Smartpak and they put the order through for me and gave me 50 smartpak singles of bute (each containing 1 gram) This was PERFECT for emergencies and whatnot, and this way, you just open the pak and dump it into your horse's bucket. No grinding pills, no wondering how many pills you have left (since its a lot easier to see the lack of paks rather than opening your bute bottle one day and crying because you are out, lol!)
Hope all that info helps ya out. They are a very good reputable company, and their Suppliment Specialists know their stuff!