I'd avoid the two you mention and find a company that charges fee for service and not per the asset value of the account, however.If you will be investing in assets that are time sensitive, involve a lot of transactions, or will be using leverage like a mortgage, then a Solo 401(k) - assuming you qualify as self employed - will be a much more flexible, and powerful tool.  

I have great personal credit and am trying to build business credit but am wary of giving any sensitive information to these types of organizations without at a bare minimum talking to my BP friends who may have seen this type of advertising before.

I know there is a bevy of price sensitive users too.

Remember, these things can get sensitive, so keeping the tone respectful in your letter is key.

If you're in a time-sensitive situation, a lender with a quick turnaround time can be crucial.

Rest assured, I will handle the transaction with sensitivity and respect for your family's memories."

Talk about what you will do to safeguard their money in the asset, who will be on your team to either manage or help get a prospective property on the right course.

As a landlord, you have a legal responsibility for safeguarding keys and providing a safe environment for tenants. 

We do have a good Trust Attorney, RE Attorney and CPA.Because I didn't want to seem pushy, I chose not to mention in the OP that this was a time sensitive issue.

However, if you had disclosed the transaction in the beginning and provided the lender with adequate safeguards, they, either by written acknowledgement by the lender or by their silence, can constitute acceptance of the deal and when rates increase, they will be in a very difficult position to call the note at that time.