Generally such discussions only take place between vaisnavas - if a person is not convinced about the exclusive position of visnu, trying to elaborate upon the greater/lesser distinctions between incarnations simply results in more confusionAn avatar, though it is a 'purna-avatar' (Krshna) is in no way superior to Narayana/MahaVishnu. This is the stand of these Acharyas. What is your / hare krisha stand ?
So for current intents and purposes, in the ultimate sense, there is no difference between any of visnu's incarnations, just like there is no essential difference between a person at their workplace and a person with their family (its still the same person).
BTW - this is the view of a vaisnava, regardless of whatever sampradaya they are coming under