Unless you've lived and smoked in a majority of the states, with one from at least every American region, this question is pretty much nothing but speculation/assumption. Where I live nobody would assume there's a big Mary Jane culture, but it's always just in the cities beneath the mainstream radar.
But yeah, anywhere in the south/southeast, 'drugs' are categorically labeled the same across the board in terms of how dangerous they are just by being illegal or not. But, at the same time, it's not like that information helps out all the sorry souls who got cases for Mary Jane in New York, which is comparatively an extremely liberal state.
All I know is that where I live in the south if you get caught with any amount of weed, you go to jail immediately - that's the end of the discussion. I'd just be interested to find out what states you're more likely to just get a ticket/court date and then you can go on your way. Other than that, objectively, outside of the Colorado/West Coast area, I don't really see the big difference - weed's still illegal and cops are still going to harass you over it regardless of how they do it.