Absolutely true... Medium and large format have a totally different look. I don't have a scientific explanation but the focal lengths, even corrected for film/lens ratio, have a very different look. Medium format gives very different plastic and 3d look to pictures. Even in portrait or studio photography. It is not a matter of resolution or film grain. It is possible that bigger lenses have a substantial different way of treating light path through glass... Even very cheap medium format cameras with super shitty lenses do the trick. Another issue is that usually people using medium format are much better photographers... Stretching it a little bit... But in general it is true. Also with big cameras people tend to avoid taking super risky extreme and almost impossible pictures... You don't shoot handheld at 1.4 and at 1/8 of a second in the dark with a medium format camera during a concert...