Most people who have tried the prototype have found it a bit fiendish. My brother (with an MSci from Cambridge) had a slightly different experience.
His complaint was that the mechanism took the jeopardy out of quizzing. What he really enjoys in a quiz, apparently, is having to balance his level of certainty against a fixed scoring system. Being quite bright, he has always been a good guesser and most quizzes tend to reward this disproportionately.
This maybe puts paid to my fanciful ideas that this might make a good TV/social quiz mechanism. However, maybe a little bit of fun is a fair sacrifice in return for quality data.