The DVD description is right, If you like the TV Alan you'll love the live Alan, and if you don't like the TV Alan, you'll love the live Alan even more,
The persona you see on QI and Johnathan Creek is definatly tweaked to suit a specific audience, wheras the the live Alan is all real, and all funny.
A lot like Jeff Green in the types of jokes he tells and in the delivery, but with many topics such as ice skating at the Olympics and keeping his cats under conrol.
A highly recomended DVD, Top of my collection
PS, I think he was rather drunk when filming this.