I like on the Digital Storm site where they say "Extreme Cooling" then "Standard Factory Heat-sink and Fan." That really is extreme!
My guess is if you played the market for a few weeks, subscribing to Newegg emails, watching prices to price match, scouring bundles etc, you could save more than the $100 difference between the linked build and pcpartpicker. I think I was $300 or more under the 'list' price just plugging things in to pcpartpicker on my build last fall, but that was being anal about watching prices daily, having a range of components to build with, actually mailing in rebates, etc. If you care about saving money or that sounds like part of the fun, why not give it a go?
If Dell weren't involved, would you go Alienware? Because they've never really been considered a cheaper custom builder, and you might consider even a more expensive place like Falcon NW to be a good value because they're good quality and good warranties and stuff like that, even though they're expensive. Hell, they'll even get you a stable, tested OC if you want them to.
Are you interested in buying/building yourself or is that completely off the table? Some people just aren't too eager because they've never done it, and some people refuse. Gotta know that first, I suppose, because building yourself is usually always the first option for situations like this.