The 6 star foods use the best quality ingredients fit for a dog. The protein content in the 6 star foods is usually high. For a healthy, active dog with the no health problems or allergies I would go towards the 5 and 6 star high protein kibbles. The 4 and 5 star foods are still good quality foods.
There is no right or wrong. The Wellness overall uses better ingredients but the trade-off is it might be too rich than what your dog is used to. You can definitely try it and slowly weed him on it. If you find that food makes his tummy upset try the DVP's Natural Balance or California Natural. However, those might not work either.
At the end of the day Nutro is one of the better grocery store brands.
