I think there's quite a few of us on here that are with Fidelity and prefer them for their customer service and available tools/website.
Can you explain what you like better about Fidelity's website and tools? My last 401(k) was run by Fidelity and I didn't find anything about their web experience was noticeably better than Vanguard's, but your mileage may vary.
I'm sure it's purely personal opinion, but I've tried several times to navigate Vanguard's website and it is very messy compared to Fido - I don't like how they arrange their info and some of it is more difficult to track down.
Fido's regular tools/website access are slightly different from the ones available for the 401Ks; I've got both, and the 401k section is presented differently and the info is compartmentalized and in some cases doesn't provide the full experience as with taxable/IRAs (at least in my case). While pulling 401k statements/info isn't complicated, the regular account access allows for all sorts of aggregate info and chart exports that are quite nice. All of Fido's tools and programs are easy to use and pretty extensive in scope, and I like their customer service; I always get my questions answered pretty much instantly, while I've seen folks on here complain about the lack of knowledge and issue resolution with Vanguard's reps (Vanguard peeps are probably very nice, but they don't seem as well trained or knowledgeable).
Since I'm not paying any more than I would with Vanguard (I have all Spartan index funds, so the difference is probably within 0.01% if that) I am quite happy with Fido.