The one-man show by Ferrell is as hilarious and crude as you'd expect from a Ferrell/McKay collaboration. (I didn't know McKay was directing the show -- I just thought he helped develop it.) It's part stand-up and part performance with a fair amount of audience interaction. However, it's not like W. where you're amazed by the detail of the performance. If you've seen Ferrell on SNL as Bush, picture a longer, R-rated version of that. But Ferrell manages to handle the serious moments (9/11, Katrina, Iraq) deftly and while it's clearly a comedy show, I don't think you'd walk away from it thinking it was "fair to Bush."
It's really quotable, too. I definitely am going to buy the DVD of the special when it comes out.