There are some potential drawbacks, of course. They are illiquid. Minimum holding period is 7 yrs. The fees are substantial. Leverage can cause margin calls or forced liquidations.
Contributors lose their ability to vote their shares.
An issue for many insiders. As to the tax-free income, I need more details. BUT, their gains have been deferred not eliminated. He said it has nothing to do with a charitable trust. Here's an ABC explanation.