Both Johnny/Rod and Mike do fantastic classes for an experienced cook and competitor. Yes they are worth the money IMHO. But understand they show you how they cook. You need to know how to cook good BBQ to get the most out of the class. You need to be comfortable enough with your cooker to translate their processes to work for you on your cooker.
It's not a silver bullet and you need to take what they tell you and work with it. I spent 2 months practicing cooking chicken and ribs after the Mike Davis class. Results in competition since Chicken - did not place, 1st, 2nd and 1st. Ribs - did not place, 3rd, 3rd 2nd. I think the classes have paid for themselves. In 6 years I never had TOY points in chicken and this year so far 28 points. I'll certainly be in the top 100 nationally and maybe the top 50 this year and only do 7 contests including the Royal.