TL/DR: Do your homework, figure out your AA, ask questions here, and once you're ready, invest with Vanguard (or Fido if you're so inclined) and SELF MANAGE a simple 2-4 fund portfolio. Don't over-complicate things.
Long version:
Are you trying to set up for your company or just for yourself? The way you've worded your post seems to be that you're investigating options for a small business, but I suspect that is not the case...
If you are looking for the best place to house your investment/retirement accounts/portfolio, then Vanguard is a no-brainer. You do not need to have them manage it for you. You should first do your homework - in other words, learn about how to invest and figure out what your goals are and your comfort levels with general volatility, and then decide your asset allocation and THEN open the appropriate accounts (taxable brokerage, traditional or Roth IRAs, etc) with the company that best suits your needs.
Start here:
http://jlcollinsnh.com/stock-series/ with either Mr. Collins' book or read through the series on his website. Then head over to Bogleheads site, and read about how to write an
investment policy statement, and figure out your
asset allocation. Do some research on
lazy portfolios there as well.
American Funds is a big NO. All of their funds to my recollection are loaded funds - meaning they take a large cut off the top just to give them your money to invest, and then they charge you an additional high expense ratio to stay invested with them and that management fee is awful (and additional to their expense ratios AND the load fees). They're little better than Edward Jones (EJ in my opinion: a terrible, horrible, awful, should be ashamed of themselves type of company). Steer way clear of any company that wants to charge you a load fee or offers "class" type of investments because it is all crap designed to put more of your money in their pockets.
Vanguard is the gold standard. They are not "claiming" that - they literally wrote the book on low cost investing. Vanguard was founded by John C. Bogle, the guy that came up with index funds and the company is founded on the principles of low cost, market tracking funds... you really can't do better than them insofar as a trust-worthy, solid investment group that isn't out to make themselves huge profits off of your money. Vanguard is owned by the funds themselves and, as a result, is owned by the investors in the funds. Vanguard overall seems to expect their investors to be more well-versed in investing/market knowledge, so it may be a bit of a learning curve starting out with them if you don't know what you're doing (totally my own opinion and full disclosure, I use Fidelity for my investments, but I was a total noob starting out). There are several other companies that aren't bad, but if you can choose, and you're halfway able to understand how investing works, Vanguard should be your first choice.
Fidelity is great as long as you self manage and stay away from their high fee funds or pay someone to manage your portfolio. In order to stay a leader in the investment field, they have a whole series of index funds that are as good as Vanguard's and their customer service/perks are arguably better than Vanguard. If you feel the need for a bit more handholding (I did), then Fidelity might be more in line, but do your homework and stick with their low cost Boglehead style funds outlined
here.
And I've never been told Fido's fees are "hidden in the plan." Their professional management fees are a percentage of the value of the portfolio under management. Always has been to my knowledge. So that, plus whatever the expense ratios on the funds they set up would be what you would pay, same as Vanguard. But why on earth would you do that (even at Vanguard) when just a little bit of reading (the links above) and some time spent asking questions/reading on this forum will get you all the ability and confidence you need to select a lazy portfolio asset allocation of 2-4 funds, open those accounts, and throw your money in there. Most folks don't even have to look at their portfolio but once or twice a year (if that) to check and see if rebalancing is needed, and that generally can be figured out in under an hour.
If you can figure out how to drive a car, hold down a job and keep the bills paid... you can manage your own investment/retirement portfolio. ;)