The principals he presents are sound and are a good introductory concepts for anyone who’s interested in financial intelligence.
His biggest contribution is his cash flow game which takes very dry material and makes it accessible for kids and non-financially literate adults.
As for his seminar business, like most seminar businesses, are mostly to handhold and entertain by reiterating everything he’s already presents in his books.
As for him being shady, I don’t really have any references for that. His books led me to another info-entrepreneur’s nothing down RE investing. That material led me to buy three houses in three weeks with no cash nor credit to my name. The next deal led to the next, so on and so forth. For someone coming from a blue collar background, receiving big checks was an eye-opener. This especially underlined the value of acting on timely asymmetrical information to match very specific sellers to equally specific buyers.
Even though I grew fond of working with distressed RE, the change of fortune I witnessed repeatedly with folks and their property had me realize I had inner issues around feeling predatorial in relating to peoples mis-fortunes.
I stopped active involvement in the biz when I experienced the same unintended mis-fortunes and experienced the same distressed circumstances.
It became clear that the ‘means are more important than the result’ at least for me.