How good is Merrick dog food?

My dog didn't like the Merrick brands when I introduced them. I think it was the peas and extras in it that my dog didn't really like. He doesn't eat fruit, veggies or sweets at all. Merrick has a little of these. The wet food he wouldn't touch either. But I have him on BG. (Before Grain) chicken kibble which is the upscale Merrick food with a slightly higher protein. He seems to like the more meaty kibble and doesn't have the fruits and veggies of Merrick. Before Grain is a 5 star out of 5 star rated kibble because it doesn't have fillers. The kibble for Merrick and Before Grain is small so it is easier to eat I think for small or mediium dogs. Not sure if a larger dog like yours would like small kibble. The size of small peas.