Gracie Jiu-Jitsu has proven itself that it is the most complete and most effective martial art in existence.  There is no valid example against it.  I’m a die hard wrestler, but it is incomplete, it does not have striking or kicking.  Same with boxing it is incomplete, it has no ground fighting skills.  Karate and Tai Kwan Do both do not have ground fighting.  To be a complete art you have to include all of them.