My parents took the HMI last fall. Ifs not so much what you learn, but more about thinking about what you do before you make the decisions that are made on your farm. It gets you looking at quality of life, and where you want to be, and from there, you check to see if the management decisions, send you, your family and farm in that direction.
The new decision making process has you looking a what you are doing, and asking yourself, What would happen if I did it another way?
The group you will learn with, can become a "peer group" that can give constructive support should you bounce a problem or situation for the group to discuss. Their group is mostly beef producers, but they tell me that there are groups that focus around grain production too. The whole idea to enjoy what you do, by knowing where you are headed, by planning and focusing on that plan.
BTW....... I'm just taking dictation, this is what they are telling me.
Check out http://www.holisticmanagement.org/
They tell me its complicated to explain it.