I used to love Derrens shows because they involved a bit of light psychology, maths, mind tricks etc... and if you look at some of his earlier shows, he did use a more credible view of psychology than he currently seems to employ.
Of course, I always knew a lot of it was showmanship, but I noticed he started using that term a lot more recently, and now it seems his shows are all 100% showmanship and the original draw of intelligence and psychology has vanished without a trace!