I have no experience using it, but ever intrigued I did take a look at the web site.
It's often difficult to get to the bottom of what's in dog food but it should be fairly easy to test one claim. That is "you only need to feed small amounts". The metabolisable energy content (Kronch Active) is 3600kcal/kg which is perfectly in line with Acana, which I use, and Royal Canin Cocker breed specific food. (not sure which RC food you use). It's therefore hard to see how you could feed significantly less food without your dog losing weight.
Their big claim of course is the use of salmon and the salmon oil content. In fact, there is only 16% salmon, with rest of the meat content coming from unspecified dried fish meal. If you take into account the water content of the salmon it probably represents only about 7% of the dry, finished product. They don't seem to give any figures for the omega 3 content but given that it oxidises quickly, my preference is to give a separate supplement.
Apart from that, it does use maize (not great) and the fat ingredient is described as vegetable fat/animal fat (definitely not good). The Kronch Main food looks worse with a good dollop of wheat as the main ingredient.
Doesn't look that great to me.