My father-in-law swears by pellets, here's his argument.
He says that because of the amount of waste associated with hay, even before feeding, just in transport, storage, and carrying it out to the horse, that pellets actually end up being more cost effective. Not to mention the ease of feeding, the fact that it takes up less space and is cleaner, it's easier for long pack trips or traveling long distances in the trailer, and its easier to measure than weighing hay.
I have always fed hay, I have cared for a few horses that needed pellets for a special reason, like they were older and had difficulty chewing, or cough problems associated with the dust from hay, but never for a horse that didn't need it. I also feel like a horse should take more time to eat, to keep their diet closer to their natural grazing eating habits.
But what are your thoughts and opinions on the matter? Do you think the amount of hay wasted actually makes pellets comparable in cost?