Tishler has some great videos and just looking at the one on stance helped me more than all videos I have watched. BUT, that said, I spent a long time looking at different videos of his and was ready to toss him aside because the quality of the videos and the way his voice came across got to be annoying. Additionally, like all the "professional teachers" they have more to say on a technical side than one can apply.
Klassen tries to keep it simple although he gets to wordy also.
The bottom line is:
Whether it is Tishler or Klassen or McLean or Haney they want you to buy their DVD's or programs or go to their schools....
If you can get on tip from any of the FREE instruction on youtube PRACTICE it!! You see, you can listen to all of these guys but at no time do they REALLY REALLY stress practice. It seems it is just an afterthought and it gets buried in their instruction. WHY? Because if you practice just a few free tips and master them you may not need to buy anything and then they don't make money.
Tishler was instructing Mark Wertz. If Mark was smart he would be taking notes and taking videos (with sound) of what Tishler is saying so he could refer back to them in the future and also to review them (like practicing) so that when on the course he can mentally have them as an arsenal to fix his swing if it goes wrong. Professionals like Tiger Woods rely on others to help them because they have the money. If they were REALLY smart, they would be compiling all the info that is given to them so that they could review it at their leisure. But then, like I said, they have the money and I don't. As Pirot, the Agatha Christy detective, says use the gray cells.