So I work in a skate shop and we have a few different Blazers in at the moment, Chucka XT, GT, Low, Low XT, Hi. I've just had a good inspection of them all and the main difference I noticed was that the Chucka seems to be the only one that actually uses a noticeably different compound of rubber..
When you a run a finger along the tread lines, they feel much harder than the other Blazers, in which case they might not be so grippy out the box but they should last longer.
They all seem to differ a little between models in terms of the spacing/sizing of the tread lines.
Also, I don't know why they're using Ishod to promote two different models, like someone just said, he just came out with the mismatch Dunks so why not use one of their other many pros to promote the shoe?