I've heard that taking that approach comes with a lot of a rules on how you can use your money. For example, if you make a profit from rent, you can't take it out in cash (it has to be reinvested into the business). Also, if you want to make an improvement to your property, you are required to hire someone to do the work instead of doing it yourself.

I could be totally wrong about this because I haven't done a lot of research. My plan is to use regular cash for down payments on traditional mortgages. I haven't decided what to do with my 401k yet, but I definitely want to use it even if that means paying the fee to pull it out in cash.