Where should a U.S. business owner open a Simplified Employee Pension account?

I am self-employed and own a business with a few employees. We are doing reasonably well. I want to open a SEP account but every investment house I consider is “clearly the best”, just ask them. Fidelity, Vanguard, Chase, etc. – they all sound the same. They all follow the same IRS rules for investing income. They all have a multitude of funds with low expense ratios around 0.10%. They all have web access. They all say they don’t charge fees. So what is the difference? They are bankers so, frankly, I don’t trust any of them. Does anyone have any experience with this? Who do you like?