Oh goodness, no...
I use Roux on big cubes.
Anywho. This has been debated over and over again. Both roux and Fridrich have their upsides and downsides but they're equally "fast." I feel that the only reason why many people do Roux is the mentality that "most of the fast people" use CFOP. However, it has been proven that Roux is capable of being just as fast at CFOP by Big Green and Kirjava. Choosing a method simply because someone is faster with it is just stupid.
Personally I have been using Roux for well around 3 years now. I'm avging betweein 12-13. For OH I'm do about 23 with a 17 single. Here's what I think are the pros and cons about each method.
CFOP
Pros
CFOP is very fast and uses lots of algorithms. All you have to really do is spit algs back out which is good and repetitive knowing all you have to do is "the same thing over and over again." People who learned an LBL beginner method will have an easy time transitioning to CFOP. Also you can apply the method to more puzzles like big cubes and megaminx.
Cons
I feel like the fun factor in CFOP is very limited. The amount of algs to a beginner will seems like a shock at first, but all you really need to do is practice them. I feel like some people who use CFOP really don't understand how the cube "works" since you keep using preset algs. There is no exploration value with it for some people who just want to be fast IMO.
Roux
Pros
A fast block building method. Roux generally take less moves than CFOP (STM) and ends with <M,U> which can be fast for a lot people. There isn't as many algorithms in Roux in comparison to CFOP but knowing more algs can only help. Kirjava has done sub-15 using only 2 algs. In my experience, I've done sub-17 using 9 algs from 4LLL. Personally, I find Roux more fun since of the different solutions to blocks almost every time. I find that a majority of people who over block building methods (not just Roux) know the cube and how pieces move, etc.
Cons
Block building does take a while to used to if you started with a basic LBL beginner method. Finding blocks can be difficult at first, but all you can really do is practice. Also the term "bad edge" scares people. It's not evil is just needs to be flipped. Also Roux cannot be applied so easily with certain events and on other puzzles especially minx. Also you risk more DNFs than +2 if you miss an M.
tl;dr - Both methods are fast and both have upsides and downsides.