if there was a blue belt bjj student and a jjj student (blue belt) fighting against each other who would win? why?
Who can say? Who would win out of a ninja and a samurai? Bruce Lee and Mike Tyson? Rickson Gracie and a bear? You see where this is going?
I'd bet the blue belt wins. Honestly, not only does it depend on the practitioner, it also depends on the JJJ style. I train in two JJJ styles and they're quite different in training and philosophy.
I like the fact that in my judo club we all have to travel to the regional HQ where the olympic squad train, to do our gradings and fight for gradings, that way you have to be as good as any other club to get your belt, i also like the fact that in our judo you have to fight to get graded.