Did a quick forum search and did not find this topic covered.
Let's get to the juicy stuff. I don't think anyone can deny that quality instruction is valuable. However, finding quality instruction is the trick. There are tons of former single A and college players out there who will train players. Yet, is it any good? There are dozens of slick marketers out there, some with gimmicks they sell. Who's worth their salt? Looking at hitting and pitching instruction.
Let's get some feed back on:
1) Who is the best in your state? Name the state.
2) Who is the best in your region? Obviously, tell us the region.
3) Who's the absolute best there is who is readily available to the public?
4) Who's the best, including professional team instructors/coaches with whom you'll probably never work?
Give a brief sentence or two to justify your nominees.
Hopefully PG will chime in. He has to have a pretty vast range of experience in this.