I am afraid that I am unable to shed any light on whether or not attendance is of much value as I have not been myself in the past. However I am going along this year and if there is anyone reading this who would like a lift to London from the Shropshire / Wolverhampton area (perhaps share cost of petrol & parking) then get in touch.
Hopefully it will be of some value although I think received wisdom is that to really get some value out of it you need to have a type rating and some multi crew experience already.