Executive Summary
There is no "best" combat sport. Any argument over how X is better than Y is really just semantics and self justification. What's important is the fact that you participated at a high enough level that you know you can handle 90% of the other men on the planet, and have experienced mental and physical discomforts that normal people would shrivel away from.

I have competed and coached Olympic wrestling for 68.9% of my life. I have coached world medalists, an Olympian, and at the International level. I competed at the varsity level and placed at the National level. I know the sport, I know what it does for people, and I know I have put myself through more and tougher physical and mental trials than 90% of the people on this planet. I also know that all combat sports require physical and mental conditioning that would make a normal person cry.

It is useless to say Sport A is better than Sport B, because each sport evolved to fill a niche that was not filled by another sport. It's like saying oranges are better than apples because they are more orangey. I see those arguments all the time on various subs, including this one. I have finished various tournaments with broken ribs, a torn rotator cuff, dislocated fingers, torn ACL, and great big pulsing cauliflower ears. I'll bet any boxer, Judoist, MMA'er, Karate guy, you name it, have all done the same or similar. Has the mewling little asswipe sitting across from you in the project meeting done that? Have you done that?

I have been down to 3% body fat, burning 5000 calories a day, training 3 to 4 hours a day, attending classes for 7 hours, and studying for another 5. Any high performance combat sport athlete has done the same schedule, you just might substitute work for studying. The mental skills and strength required to battle through fatigue, pain, discomfort, and sheer exhaustion are enormous. Very few people on this planet understand how to do it and how far they really can push themselves. All high performance combat sport athletes have seen this edge, have pushed beyond it, and made themselves better men for it.

Confrontation, combat, provocation, aggression, intimidation, and outright hostile actions are a daily occurrence for combat sport athletes. Go into any workplace, and what you experience is a joke compared to what you experience training and competing. People run from confrontation, shrink from aggression, cry to HR over a little intimidation. We scare people we work with because of our intensity. We scare people on the street with our body language. We have confidence in all aspects of our lives because we have pushed our selves further than normal people and know that everything else in life in easy compared to what we did in our chosen sport.

Conclusion
All combat sports provide the same fundamental frame and experience. Stop bitch fighting over which one is the best, go pick one, and do it.