They are both excellent food for your bird. Harrison's has USDA organic going for it Roudybush has no peanuts Harrison's does.
Roudybush also has a little variety now in that they recently came out with California blend having more fruit and veggies like dried peaches, apricots, plums, bell peppers, carrots, tomatoe and cabbage combined with Roudybush Daily Maintenance pellets.
Roudybush daily maintenance has has roughly 7% fat and 21% of its calories are derived from fat. Which theoretically helps in converting birds from a diet high in seed fat
With Harrison's it's best to follow their recommended regimen and use Harrisons Organic Adult Lifetime after completing a dietary program of High Potency Formula for a period of at least 6 months.
Either bird food which falls under the category of "engineered" bird food which will theoretically sustain any caged bird for a lifetime without the need of additional vitamins.
That said - there ain't no pellet trees in the rainforest so you still want to give you bird fresh fruits, veggies and nuts.
If you haven't already please feel free to take a look at our complete bird food selection - hope that helped