There are additional perspectives that there is a difference in the quality of noodles (such as the quality of buckwheat flour and variety) and that zaru soba is 'fine' while mori soba is 'average' in terms of the noodle rating.
なお、蕎麦そのもの麺質（粉質や種類など）に違いがあるとする考え方や、ざる蕎麦が「上」で盛り蕎麦が「並」とする考えもある。