Purina feeds are all I feed in my barn and I have a variety of horses. I feed my 21 YO QH Purina Senior mixed w/Purina Weight Control (basically a hay stretcher). He's a very, very easier keeper and the Senior by itself was just a little much for him, so the Weight Control gives him a little more feed while the Senior ensures he's getting all the nutrients he needs. The other horses in the barn (range from 4 YO to 10 YO - and a variety of breeds QH, TWH, Morgans & TB) get Omolene 100. I personally have never tried the Strategy but I love the Omolene 100. All the other horses in the barn (my 21 YO isn't ridden anymore) are ridden between 2 and 4 times a week and are basically just trail horses. Even the hard to keep TB does fine on the Omolene 100. Omolene 100 is specifically formulated for the pleasure/trail horse that gets ridden 2 to 3 times a week and I love it- I have never fed the Omolene 100 to a horse and had any problems w/the horse getting hot off the grain. All the horses in my barn have silky gorgeous coats, they all are barefoot and besides a daily wormer, they get no supplements- it all comes from the grain, hay and pasture they receive. There is one mare in my barn that receives Omolene 500 but she's ridden 4 - 6 days a week (on average) and is a competing barrel horse that runs almost every weekend from April to November.
So my suggestion is go w/Purina feeds. They are the only feed I use and recommend.
Edit- I just saw your user name- My old guy is a QH named Scooter too!!
16 years of feeding Purina grains