We have our Maine Coon cat for a year now and have a puppy already fed him the kitten-feed of Royal Canin. The food is highly recommended, the pieces are very large and our cat tolerates it very well. I think at this feed of Royal Canin you can not go wrong. It is well digested and it must be chewed well, especially in Maine Coon's should pay attention to the teeth. We use the feed as a complete diet, he now and then also gets meat, but mainly this feed. Be careful anyway, our second cat (normal house cat, clearance) is gewurden very thick through the lining. Apparently cats react very differently to the lining.
I can ausprechen a clear recommendation for Maine Coon cat owner, it includes everything a cat needs. Whether you want to spend the money for this food, of course, everyone has to decide for themselves. Of course there are cheaper food, but one wants only the best for the birds!