Our last gerbil (RIP) didn't like the PAH brand. I buy, for our current gerbil girl, whatever one I can get in the supermarket. She currently has Wag, and it has plenty of variety, crunchy things, seeds, a few nuts, pellets. She also gets treats, fruit, veg, gerbil chocolate, gerbil cheesy treats and bits of plain human biscuit (as long as they don't have chocolate in). <spoiled>.
I made my own. If you have a Jollyes near you, make a mix of rabbit sticks, flaked peas/corn, cereals and a few seeds. Cost a fraction of the price of bagged stuff and they ate all of it. I had the healthiest glossy gerbils... died of extreme old age! I miss them!
PAH is dreadful. Full of those grassy pellets they dont like and ovepriced!