Anum is legit. Also, have you looked at BitcoinIRA?
Amun has crap volume though (unless I am looking at the wrong site). Many days they have 0 shares traded and they seem to have at most 5k shares (so like $100k-$200k n volume) on other days.
Bitcoin IRA uses a self-directed LLC setup right? Not too comfortable with those for the reasons I outlined above. I don't trust this setup as there are too many rules that I am sure the IRS will have a field day over once BTC is worth enough. An example from Broad Financial:
"Do not apply for overdraft protection or for a line of credit for your account... by doing so, you will be issuing a personal guarantee on behalf of your solo 401(k) Plan/Trust which is a Prohibited Transaction."
Really stupid rules like that. Most banks automatically apply this, especially if you already have other accounts at the bank.
Bitcoin IRA is not a self directed LLC setup.