Like many other 'methodologies', it has uncritical advocacy. (http://blog.objectmentor.com/articles/2009/10/07/tdd-derange...) (HN discussion: http://news.ycombinator.com/item?id=866707)
I agree that automatic testing is nearly always a net gain, but using tests themselves as the primary driver for the design process suggests to me that the developer has little other design experience to draw upon.