I ran the W.D, and several others like it! The W.D is, by far, the most organized and well run "muddy" event that I've run. I did four of them this past year, and I'm signed up for the W.D here in North Texas in April 2011 as well. The obstacles aren't really THAT challenging, to be honest. At some points, really all they did was slow you down because they caused a bottleneck within the course. Regardless, it was a really fun even to run. There is a lot to do afterwards too, and a ton of eye candy as well.
Where are you at, and what dash are you looking at?