to me Fitness is good as i m doing this for years, and i get all the benefits from it which are discussed above in favor of Yoga!
Why not do both? Yoga helps fitness and fitness can aid a yoga practice. Both are great for improving body and mind and both can be adjusted in terms of intensity to suit our needs.
IN general, can easy mix them, fitness is my preference as to make more physical activation, but in recuperation time, ending of any training usually can use several yoga exercises before the last cardio part.