Looking at the ingredient lists:
Pure Vita:
Salmon, salmon meal, pea protein, pea starch, sunflower oil, flax seeds, pea flour, natural salmon flavor, sunflower meal, alfalfa, peas, yeast extract, tomato pomace, dried brewers yeast, phosphoric acid, potassium chloride, calcium carbonate, salt, DL methionine, choline chloride, carrots, minerals (iron proteinate, zinc proteinate, copper proteinate, manganese proteinate, cobalt proteinate), taurine, cranberries, apricots, cherries, minerals (ferrous sulfate, zinc sulfate, zinc oxide, copper sulfate, manganous oxide, sodium selenite, calcium iodate, cobalt carbonate), turmeric, dried chicory root, vitamins (vitamin A acetate, vitamin D3 supplement, vitamin E supplement, niacin, d-calcium pantothenate, thiamine mononitrate, riboflavin supplement, pyridoxine hydrochloride, folic acid, biotin, vitamin B12 supplement), ascorbic acid (source of vitamin C), inositol, yucca schidigera extract, rosemary extract, yeast culture (Saccharomyces cerevisiae), dried Lactobacillus acidophilus fermentation product, dried Enterococcus faecium fermentation product, dried Aspergillus niger fermentation product, dried Bacillus subtillis fermentation product.
Blue Buffalo:
Deboned Turkey, Turkey Meal, Pea Starch, Pea Protein, Potatoes, Pea Fiber, Canola Oil (preserved with Mixed Tocopherols), Peas, Natural Turkey Flavor, Flaxseed (source of Omega 3 and 6 Fatty Acids), Whole Carrots, Cranberries, Blueberries, Barley Grass, Dried Parsley, Alfalfa Meal, Dried Kelp, Taurine, Yucca Schidigera Extract, L-Carnitine, L-Lysine, Turmeric, Oil of Rosemary, Dried Chicory Root, Beta Carotene, Vitamin A Supplement, Thiamine Mononitrate (Vitamin B1), Riboflavin (Vitamin B2), Niacin (Vitamin B3), d-Calcium Pantothenate (Vitamin B5), Pyridoxine Hydrochloride (Vitamin B6), Biotin (Vitamin B7), Folic Acid (Vitamin B9), Vitamin B12 Supplement, Calcium Ascorbate (source of Vitamin C), Vitamin D3 Supplement, Vitamin E Supplement, Iron Amino Acid Chelate, Zinc Amino Acid Chelate, Manganese Amino Acid Chelate, Copper Amino Acid Chelate, Choline Chloride, Sodium Selenite, Calcium Iodate, Salt, Caramel, Potassium Chloride, Calcium Carbonate, Dicalcium Phosphate, Dried Yeast (source of Saccharomyces cerevisiae), Dried Lactobacillus acidophilus fermentation product, Dried Bacillus subtilis fermentation product, Dried Enterococcus faecium fermentation product
Both are at 30% protein. The Blue adds potato in addition to the peas. They are pretty similar.