I have found some value in his books and I listen to his podcasts from time to time to learn about different things going on in the financial world.
When it comes to investing, I believe it is something personal that we all have to figure out on our own what advice to follow and if it is something we are willing to commit to and take a risk on personally.
I don't believe one key person has the magic investment strategy to make all the money, I believe there are multiple factors that play a role in the investment strategy you choose.
I personally know a guy who followed Robert Kiyosaki's principles and is now a multi-millionaire but even he had to do some things differently based on his personal experiences.
When it comes to the seminars a lot of these "gurus" offer I have never considered it to be worth the money. I have gone to a free class once for one of those guys only to quickly realize its just about selling you on the next step up.
When it comes to investing, I believe that reading lots of books, researching and forming your own strategies is the best way to go.