Simply Nourish looks to be a good food with good ingredients. I would go with it (the grain free preferable).
Do Not just feed any food because the dog or someones dog did "good" on it. Only pick from quality foods to begin with. I hear people say their dog did good, looked good, lived for so many years, etc., while feeding a poor quality food. I also hear people say they tried the better brands and the dog didn't do good. There are many reasons for that. Improperly switching foods is most likely. This process can take a month in some cases. The better brands also have good antioxidants that may cause dogs to have the runs, due to the toxins being flushed from their system. Another cause is intolerance and allergies to ingredients such as chicken. You'd think that the dog does good on chicken since that's what the poor quality brands claims to be in the food. Well, Purina's chicken by-product or poultry by-product, doesn't contain any meat. By-products are what's left over after de-feathering and removing all meats. I know some Purina products have chicken listed as the first ingredient. This is a scam... Ingredients are listed by weight. Chicken, is about 70% water weight. Chicken meal is what you are looking for. Meal is the chicken cooked, ground up, and ready to put into the food. It's like chicken concentrate. So, if a dog has an intolerance to chicken, you may not know about it feeding a poor quality brand like Purina, Ol' Roy, Science Diet, etc. Although, when you try to switch to a good brand with tons of chicken, you'll then see a problem. That's when people blame the brand. I've seen it many times. I first have them switch off chicken to a fish or red meat with the same brand to see if it solves the problem. 90% of the time it does.
Please check out the videos (not my videos) how to choose a dog food on my web site, aepets.com. Also check out dogfoodadvisor.com to get an insight on any brand you are thinking about.