I do a rotation diet. Currently I'm feeding Merrick, but I've fed everything from Nature's Variety Instinct to Orijen to Fromm and many, many more. Always grain free. I change brands after every 12-15 lb bag, but I have a small dog so it takes a few months to get through one bag. I like trying different brands, and I really think my dog appreciates the variety. These days I can switch his food cold turkey without having to do the annoying transition thing, which is nice.