I think the point is that every brand fits differently, obviously my shoes of choice are not made by K2 so I don't expect them to fit the same. I judge a boot fit by personal comfort and how well it locks your foot in. i.e. not too small to have my toes crushed but not too big to have heel lift. Nobody (not even a boot salesman) can tell you how well a boot feels, if it's uncomfortable to walk in for 10 min how comfortable do you think it'll be when you're snowboarding the full day in freezing temperatures?
Moral of the story, try boots until you find ones that fit properly.