I've been a fan of Mr. Heck's work for a while. It's always interesting to get new perspectives on design choices for custom projects.
You could buy two nice laptops, build at least 2 really nice gaming rigs, or build one Ludicrous-speed desktop setup for the price of this. I wouldn't buy it unless I was filthy rich.
I would love to build something like this myself though- the main challenge would be finding an elegant yet functional way to handle the power brick (pun fully intended), wireless controller gear, and other non-standard hardware.