I stopped watching that when Doug Richard left...
(I'm sure the others are great - but uk web investors are the ones I try to obsessivley keep on my radar.)
I've watched quite a few DD episodes. Doug was the most tech-hip Dragon the show has ever had. I think he had the best grasp of, and the most interest in, scalable startups and modern technology. I wouldn't expect the other Dragons to do someday be doing something like this: http://www.schoolforstartups.co.uk Or this: http://trutap.com
I think most people watch it to see a real car crash. When I've watched it, which isn't that often I've been shocked by how bad some of the pitches have been.