As you probably already know, everyone feeds in a way that suits their horses and their own beliefs as to what is best. I'll tell you what we're doing currently:
14 yr old "hard keeper" - we've been concerned off and on since we got her in 2009 that she might have ulcers. She recently "took a turn for the worse" behavior wise. Upon consultation with my vet, we started her on a 28 day of Gastro Guard to treat for ulcers. Further research showed me that feeding her the sweet feed (Omolene 300) we've been feeding her is the worst thing for her if she does have ulcers. I've read from several sources that any grain should be avoided and just forage, forage and more forage, including alfalfa hay or pellets. That's what we've done in recent weeks. She wasn't eating much feed anyway, so taking it away wasn't a big shock to her system. She's getting a pelleted supplment (ration balancer) alone along with ever increasing pasture time and alfalfa mixed hay (which we've been using for 2 years now, I think).
The 5 younger mares (1-four year old, 4-three year olds) are being switched from Purina's Minature/Pony feed to the same ration balancer as the hard keeper. They get much more limited pasture time and wear muzzles when they are on the pasture. And I give them hay when they aren't on the pasture. I try to give them about 1% of their body weight at this time of year. 2% or more in the winter depending on how cold of a winter we're having (it can vary a lot in Maryland). A 5 of these mares are in great condition as far as having healthy coats, eyes, hooves, but all are at varying degrees of overweight. I'd say between 6-8's on the body scale.
In the three years I've had these horses, I've come to the conclusion that for me, simple is best. I've been lucky in that only 1 horse out of six needs "something different". Others on this board have more horses and/or horses with varying needs requiring different approaches even on the same farm.