So I went and paid for a one month subscription to see all of the MotoVudu videos available on the website. There's a lot, over 100 videos. Some are quite short, only a minute or two, others are longer. It's basically a bunch of videos of Simon giving tips about riding (and other things related to riding). I'd love to read his book but it's not available electronically and I'd prefer to download it and read it on my iPad while on a plane. So my feedback is based purely on the videos and the public stuff on his website. A lot of it is good information and will definitely help riders improve.
One of things that jumps out at me about the quoted article above by Simon: "In all my years instructing on circuit I am yet to come across a very fast rider using strictly what CSS teaches". My first response to this is that very fast riders don't need Simon's coaching so that's probably why he's never come across one (it's not hard to find a list of very fast riders trained by CSS) The very first comment at the bottom of that article is by someone who had been "using CSS technique of getting balancing throttle applied straight after turn in" - that's not what I remember CSS teaching - we all know the throttle control rule, and it's not about "balancing" throttle. So as Dylan pointed out, the former students that Simon has been coaching aren't even practicing what they've been taught at CSS.
He teaches pushing yourself up against the tank so that the tank can hold you under braking forces, BUT he also says to lock your arms on the bars under braking. Once the braking is done you're supposed to relax the arms and lean your upper body forward and on the inside of the bike. Then in another video he talks about how to many people have too much input on the bars. Well guess why that is? It's because riders at the level he seems to be coaching, can't go from fully locked arms to leaning forward with relaxed arms quick enough so the arms still locked or partially locked while they are trying to steer the bike. He also talks about letting the rear move around under braking, which IMO is a result of what he's teaching, not a something you should be aiming to do.
It's not my intention to ridicule Simon's coaching, because as I said at the start there's a lot of good stuff there. There's a really good, balanced, review of the MotoVudu DVD (the content of which is available with the one month subscription on the website) here: https://lifeatlean.com/motovudu-dark-art-of-performance-dvd-review/ and I agree with everything in that review.
The only negative comments I've seen of CSS are from people who clearly haven't understood the drills they were supposed to be practicing. One guy complained that a CSS coach told him he would go faster without getting his knee down. The drill he was practicing before being told this was Rider Input - he was trying so much to get the knee down that he was white knuckling the bars. Knee down doesn't make you fast (though fast riders can get the knee down whenever required/desired). I have video of me getting the knee down in a carpark doing figure 8's in 1st gear at not much more than walking pace.
As for which methods are the best/fastest, it takes a lot more than learning riding techniques at a few riding schools to be very fast. A lot of riders suffer way too much from paralysis by analysis, when what they need to do is get more track time and practice!