With the Current product announcement and their own controllers out now, there isn't much reason to build your own economically speaking (I was a little shocked at how low their MSRP is), but this does allow you more control and the ability to tailor it exactly to your needs.
Yeah sorry to let that cat out of the bag on that one. There are still people wanting to have more control than a "out of the box" controller though. Anything I buy, I usually tweak like a mad scientist. Love the DIY picture BTW indychus =)