Hey lula,
First, I do not find the information that Shawn prefers the S400 speaker over the Tekton models in any of his statements in his videos. I made the Double Impact Monitor one of the products of the 2018 year award winners for hometheaterreview.com. If you have not read my review on this speaker, take a look, its an amazing performer. Two other websites also selected it for their products of the year. You should also consider that the Tekton is a much easier speaker to drive then the Buchardt's.