Had an interesting little discussion with Jeff Burger that brought up something interesting.
Jeff points out, rightly, that some styles have a proven track record in certain environments and context. Sport is one of the easiest places to see this, because sports performance is easily trackable, measurable, and verifiable (as opposed to combative success, which is messy and hard to verify, or spiritual enlightenment, which has no system for verification that I’m aware of).
Modern Mixed Martial Arts competition is a great example of this: people in this sport tend to train in some combination of Brazilian Jiu-jitsu, Muay Thai, Boxing, Wrestling, and Judo. There are occasional outliers, like Lyoto Machida (whose claims Shotokan Karate as his primary style), but they are rare.
But rare as the outliers are, they matter. I wouldn’t expect a Shotokan exponent to do well in MMA, but Machida has. Granted, his training does not look like that of a typical Shotokan practitioner, but that’s sort of my point. Machida’s father found a way to modify the training to make it appropriate for MMA. The coach there mattered more than the style.
That said, when you are considering your goals, it is worth considering if there are particular styles or systems that have been well received or proven to work well in that environment. Muay Thai produces more successufl kickboxers than Tae Kwon Do does. Muay Thai has never produced an Olympic TKD medalist, however.
Goals and coaches still matter more, in my opinion, but the style itself can serve as a useful guideline.