Just my opinion, but not really worth switching.
If it's a workplace-sponsored type of account, you wouldn't be able to anyway until after you left that job (roll to an IRA).
Vanguard is the flagship for index fund investing, and one of the selling points about them is the fact that they are not a shareholder-owned (i.e. "for profit") company. So they keep the costs for everything low, and pass the savings on to the investors. They are a great company, and you wouldn't be wrong to go with them.
That being said, as long as you're not using "professionally managed" funds, paying for extra services, or going into the funds that have high expense ratios, Fidelity is highly competitive and in some cases, better than Vanguard. They have index funds (Spartan series) that are the same or within .02% expense of Vanguard's similar funds (just like the one you've already found, and basically, to me that .02% difference on a few funds is worth it for the other perks). They have superior customer service. They have a website interface that is much more comprehensive and allows you to do much, much more than Vanguard. I did my research last year, and ended up moving all my accounts to Fid (and have my 401k there) and I am very happy with them.
Check out this bogleheads link regarding using Fid funds:
http://www.bogleheads.org/wiki/Fidelity