I feed Kirkland (sold* only at COSTCOs) which is made by the company that also makes Diamond -- as well as Chicken Soup and a variety of other brands.
When I can't easily make the 120 mile roundtrip into Lenexa, KS, to refresh my Kirkland supply, I buy a smaller bag of Diamond locally.
Diamond is a quality food -- on a similar level with Eukanuba, Nutro NC or Ultra, ProPlan, etc.*
The reason for the cheaper price is that they spend no money on advertising but put any $$$*for that into quality ingredients and instead rely on word of mouth and label readers -- like you -- to advance their sales.* Their strategy couldn't work if ALL MFRS did that but, since they don't, it can work for one person swimming against the tide.
Last year, in one of their (Diamond, et al.) Southeastern US plants, they processed some food with corn that had a toxin in it which was undetected by their quality control.* Several dogs died and more were injured.*
The company called back all products affected and reimbursed those with injuries.
In fairness to that company, similar things have also happened to other major dog food brands (as also in the recent spinach and lettuce problems). And I'm sure that NOW their quality control is at least equal to the best in the industry and possibly at the top.
Recently, the company has split their usual one Diamond line into TWO separate lines -- a less expensive Diamond, which may possibly now include more grain "fillers," as well as a more expensive "Diamond Naturals" which is more similar to the new Kirkbride formulation that includes carrots, apples, peas, cranberries, etc.
If you have a Lab puppy, my strong preference is to feed a LARGE BREED PUPPY FOOD.* Diamond makes one and maybe two brands.* Read the labels and decide on which is best.
Diamond (and their related products) is a high quality food at a very attractive price.
Puff [YF, AKC field line (from competing HT/FT breeder) 62 lbs, dob: 8-'01]