Actually, Mantus has made a number of different test videos. On one of his website pages, you will see tests using a winch on a truck with a chain/rope rode on the anchor to illustrate the holding power in that particular bottom. In another video, he summarizes the test results in three different bottoms giving the holding forces achieved in those tests. In those tests, you would have to say that Mantus was all around better. We've been a bit hard in some of our criticisms and those criticisms might be resolved a bit by reviewing all of the test series presented at this link, especially those in typical anchoring conditions:
....Test Videos | MantusAnchors
When I try to post the link above, it comes out different from what the page shows. Type in this link.