I have spoken of front of pack nutrition labels many times and provided examples of different systems.  A system can be one that appoints stars for meeting a certain criteria, or one that uses a symbol to denote healthiness, or my favorite, one that uses a multiple traffic light.  The multiple traffic light system shows whether the product is low, medium or high in amount of each nutrient most people should limit (i.e., sugar, salt, sat fat and calories).
The most important thing about a front of pack label is that it be standardized across all products, manufacturers and restaurants (if it goes to menu labeling).  Imagine how confusing it would be (and is now in the US) if each company decided what information, if any, to put on the front of a package.  
When it comes to making health and weight related dietary choices the most important disclosures are these: calories, sodium, sugar, and probably saturated fat. We need to be able to see the amount of these nutrients at a glance across items as we shop.  The traffic light system goes one better.  If the traffic light is used, a consumer does not have to do math or know the number of grams or milligrams that are recommended for any one nutrient in a daily diet.  The consumer just has to know that green is better (GO) and red should be limited or avoided (STOP).  In essence, a consumer can aim for mostly green and yellow.
The UK has begun its voluntary traffic light labeling program in grocery stores and it seems to be doing well.
When researchers and public health professionals were making the case for front of pack labels, they put together an on line quiz to test consumers understanding of nutrition labels.  It is still available, here.  I took it and suggest you do as well.