we are on natural balance LID venison and sweet potato! (canned & kibble)
Avie has some tummy issues & the limited ingredient diet of only venison(low fat%) & sweet potato works really well for us!!
sorry.. can't comment on the other NB formulas.
i think a lot of people feed the 'allergy formulas' aka the 'LID - limited ingredient diet' formulas, because there is ONLY a "LIMITED" amount of ingredients in them!! (venison & sweet potato... duck & potato...
) (which in my opinion is ideal.. especially for us!!
)