I don't think you can really say whether Roux or CFOP is better on a whole, as most of the parameters of what makes a good method vary from person to person. And Roux is definitely at least equal to CFOP, as Sean has an official average that is only 0.45 seconds away from Felik's world record, and Felik's has been cubing for almost as long as Sean has been alive. But, in my opinion, it doesn't matter which method you choose when transitioning from the beginner's method, if there is a speed block on either method, it is Sub-WR, way farther down the line than most cubers will get, both methods can get you Sub-10 and beyond, so choose the funner one. As for learning curves, CFOP is definetly easier than Roux for some parts, as last layer transitions from the beginers method, but I would say blocks are easier to learn than F2L, if presented in the proper way. But neither method requires a college degree in group theory, and you could learn either if you put enough effort into it. When I switched to Roux I wasn't thinking about whether the new method would make me faster, it just seemed more interesting and fun, so I went with it. (End of opinionated speech)