Utility classes I dislike (mixins plx) and the idea of using important with them is not a design decision I would want to pick up.
I guess my bigger problem is that Harry sells himself as an expert, stands up on stage telling people this is how they should be doing things... and here I am, no book, no stage and my specificity level gets trumped by Harry amongst certain members of my team (despite my years of qualified awesomeness across large scale, popular, public domain sites)
Thought I'd just share that with you :`P