Nothing and I mean nothing beats Prada nylon. They are all I have carried for the past several years. They wear like iron and look good doing it.
Like chessmont said though it is all about the details and their functionality.
I have the fringed leather julian and I love the back pocket for secure and easy phone access. It’s also easy to get in and out of. I also have a nylon Prada backpack and I love it for rainy days and for the sleek urban look. I probably use my julian more than my prada but when I travel I prefer the Prada for aesthetics and all-weather material.
I also have to chime in for the Julian. I have one in a rust suede from the Nordstrom Anniversary last about 2 years ago and I have used it a lot. I was really afraid that the suede would show wear and I would hate using it because I would have to be careful, however, I haven't encountered that. This doesn't apply to your black nylon bag, but it is a testament to the RM brand. I agree with everything everyone else has said about the organization and the pockets. I use the front ones for lip gloss and small bits and the back for my phone.
A friend of mine is a dance mom and she told me that all of the moms in the dance school carry the Julian because, during competition time, they can't be bothered with having their bags laying around or falling off their shoulders when they are trying to get their dancers ready.
I am not a fan of drawstring at all so I would not be drawn to the other two bags. I like that the Julian is easy to open and close with one hand and I don't have to be bothered by a flap!