Hi Henry,
Thanks for your question. All three are good foods and I obviously don't want to do a full scale critique of any foods here (you have countless other threads for that) but what I can do is tell you what sets Natural Dog apart:

With absolutely no artificial additives whatsoever - including artificial vitamins, ours it the UK's first truly 100% natural complete dog food. Every nutrient found in our foods comes from the high quality natural ingredients we use, hence our slogan - nothing else added, nothing else needed.

We use a high proportion of meat (43% in our Adult Chicken variety for example, 55% in the Puppy), combining fresh and dried meats to provide what we have found to be the best level of protein and excellent palatability.

Every ingredient we use is human grade, completely natural and (apart from the rice) is sourced from the UK.

Of course, Orijen is an excellent food, and it has certainly thrown into disarray everything we thought we knew about canine nutrition and in particular protein levels, but nevertheless, we are confident that our foods can match, if not beat Orijen in trials, plus All in One is far less expensive and is from the UK.