Huh - I hadn't realized they were. Most of guideline's copy focuses on low prices, so I assumed that that's an effective way they could differentiate themselves.

I think the important thing to understand about this space is that a custodian is required by law, and that their fees they take are (conceptually) separate from the fees your funds charge.

Hi I'm the founder. The copy is not meant to focus on low prices, but rather low expense for the participant. I understand that might be coming through. You are correct on the custodian fee, that is a pass through and having a custodian is great! Appreciate the feedback!

Not for solo 401(k) users; that would be Fidelity. Vanguard doesn't allow access to the lower-cost Admiral share classes for solo 401(k)s.