I purchased David Blair's DVD "The Secret of Golf". He has also recently uploaded a series of "Swingbuild" instructional videos on YouTube. The instruction is excellent, in my opinion.
In my opinion, the techniques taught by David Blair will work for most anyone, male or female, young or old, IF they learn and practice the full system. If someone is trying to cobble one of David's techniques to their existing swing, it's probably not going to work. I think anyone who is serious can learn the Swingbuild process and take it to the course within 1 - 2 months. It really is that easy.