ZuPreem Fruit Blend pellets seem to be popular with lots of Quakers. My QP Ralph likes Pretty Bird Daily Select fruit flavored pellets, and Higgins InTune Natural fruit flavored pellets too. He'll eat plain Roudybush pellets, but only if they're mixed in with the ones he likes better.
Clover came to me already used to Roudybush pellets. Sweet Pea hates them and hates all pellets in general because his previous owner had him on a seed diet. He now gets ground-up Roudybush and Caitec's Oven Fresh Bites (soaked) in his veggie mash and only when his crop is full, he gets a few safflower seeds.