There is a lot of variation on how custodians charge fees, so I would focus on this first in evaluating choosing a custodian for a self directed IRA.
This also means you need a more specific idea of what you intend your IRA to invest in.
I have a self directed IRA which invests in real estate, and for that I have gone with Equity Trust Company (which apparantly acquired Sterling). Equity Trust has an online no charge for ordinary course “bill pay” for paying regular property expenses which I find convenient. I am not aware of any other custodians who offer this. Other custodians will charge you for each check they write.
Their “Equity University” education program is mostly a sales pitch though which I find pretty worthless.
