I'm not a Purina fan as they tend to use least cost formulas (any thoughts, Holly? ) From my understanding, their product that is a fixed formula is Wellsolve, which is why it's the one that's more expensive.
I had horses on Strategy for several years till they "improved" their formula-then all my horses got thin.
Anymore, I wouldn't pick Strategy unless I had a race type horse. I don't like high starch feeds, period. If I had to pick a Purina product I'd go with Enriched 12 or 32, depending on hay.