Bull, TCU uses it, they're a top team, their defense is ranked top 5 basically every year, including top 1 I believe 3 out of the last 5 years. TCU runs an extremely complicated version of the 4-2-5, where the 5 DBs are seperate from the front 6, there's basically two defensive players calling seperate plays for each portion, and sometimes they also split the DBs up, one side will be in zone the other in Man to man.
So don't pull out that crap about the top teams not using it, or it not being effective.