I've just got back from the Birmingham event, it was well worth the money, 6 hours of driving and the hotel bill. It's also resulted in me ordering a Paul C Buff PLM, and a
SinghRay Vari-ND (f2.8 in blazing sunlight, with flash.

)
David is a very modest man, and extremely amiable. Certainly a very down to earth guy who can talk about a lot more stuff than just lights.
The day is completely different to the Strobist DVD's, and he even stated that he thinks differently about creating lighting today than he did then and explained a few "epiphanies" he's had over the last few years (like Ring Flash....).
There was also an hour or so where we talked about methods of increasing the value of your photography, dealing with copyright issues, and using social media to your advantage (convinced me to start tweeting last night.)
As for the lighting, I was one of the test subjects for a demonstration of clamshell/beauty lighting and he made me look really good

It was good to see him working things through, building the light and experimenting to get a great shot.
If you're going to Leeds or Edinburgh, you're in for a treat, and I'd recommend going along to the mixer the night before for a little chat and banter.
Don't bother taking a camera, and don't be afraid to ask questions.
Next up for me is a day with Joe McNally in July, slowly making up for not getting to GPP!