Full disclosure: I have everything with Fido and am 100% fine with it. I have no personal experience with Vanguard. I only am giving my opinion, based off my own experiences and things I have read here and around on other financial/frugality boards/forums.
Fidelity is as cheap if not cheaper than Vanguard - but only if you're looking at the
index funds expense ratios comparing Fido's index fund stable to Vanguard. If you use Fido's managed funds, invest in any funds that Fido would charge a fee for (like buying/selling/holding Vanguard funds in a Fido account) or pay for professional management, then you will be paying more than what you could get compared to Vanguard.
https://www.bogleheads.org/wiki/Fidelity^a comparison of index funds/ETFs for Fidelity picks (again, you lose the cheaper cost benefit of investing with Fido if you hold non-Fido funds since they will charge you transaction fees for outsider funds)
I hold a few Fido index funds - nothing else. I pay zero in management fees, and my ERs are lower than Vanguard's equivalent funds.
Vanguard's VTSAX expense ratio: 0.04%
Fidelity's FSTVX expense ratio: 0.035%
Vanguard's VBTLX expense ratio: 0.05%
Fidelity'sFSITX expense ratio: 0.045%
So it's not a huge amount, but they
are cheaper. And Fido offers much more in terms of customer service, website interface/tools/apps/calculators, etc...
You'll likely have read all about how Vanguard is shareholder owned, and how they're not in it for profits and how that's a better overall company standard/practice. Totally agree that this is good for the shareholders as the company isn't going to be a greedy corporate entity out to make more money off their clients to fill the board of directors' pockets. But unfortunately, this structure also means they don't pay their employees as well or throw god-awful amounts into developing the latest website or apps since they don't want to have a high overhead and prefer funneling most of the profits back to the shareholders, and that means they may not be the most knowledgeable or as well trained people or have the latest and greatest gadgets and tech stuff as someplace like Fido. I've seen numerous issues with getting questions answered, getting funds transferred in or out in a timely manner, and a bit of disorganization over the whole company in general and I've heard complaints at how clunky the site can be. They get the job done in the end, and there's never been a single instance where I thought they did anything wrong - just slow, confused sometimes and frustrating to deal with in some cases. I don't think this is the norm, but it has happened more than you'd like to hear about in normal circumstances.
That being said, Vanguard does have another advantage over any other financial group. They have a proprietary dividend system (patented so that means only they are allowed to use it) that minimizes cap gains/dividend taxable events. I am very spotty on how this all works, but it is something of a plus for them, and hopefully one of the Vanguard peeps can chime in with the how and why this is such a good thing to have.
My take overall is that if you are an index investor, you can get a great portfolio setup at Fido for around the same money (granted it's going to be a few hundred a year give or take), but have access to more bells and whistles since Fido is so competitive and constantly trying to beat the other guys. The index funds and other ultra-low cost funds/ETF they offer are loss leaders. They hope to entice you in and then once you're there, show you some slick managed funds or maybe partake of their paid managed funds/services at some point. The key is to never buy into the expensive stuff - if you're in it for the index funds, then always stick with that, and you'll get all the benefits of a fancy schmancy fund group with an itty bitty expense ratio.
I honestly think Vanguard is a fantastic company and should be considered as your #1 pick unless you do feel like you need a bit more help/hand-holding. I did in the beginning, and now I stay with Fido because I'm very happy with what I have and can't imagine stepping backwards on the customer service and perks I get with Fido.