We made the switch from Arden Grange for our Springer and Cocker spaniels over a year ago. We had tried other alternatives in the past but always felt they were low on nutrition because the dogs would do HUGE poos.
Wonderdog was different - it agreed with their stomachs, their poos are small and consistent and there is really no difference between Wonderdog and Arden Grange, which is more than twice the price.
I'm very cautious about feeding substandard food to the dogs just to save money. They are family members and I want them to eat well, because 2 bowls of this stuff every day is all they get.