how to select self directed IRA company

[Steve C.]

What criterion should I used to select a self directed IRA company?

I do see multiple companies from below list. 

https://www.biggerpockets.com/rei/self-directed-ira-real-estate/?utm_source=search&utm_medium=internal&utm_campaign=selfdirected

Many of them look pretty small. What happens if these company goes out of business?

Is it FDIC insured up to certain amount?

Thank you for any insight.