I have been a couple of times,4 years ago, introducing my upvc business, waste of time for that. The plumbers, sparkys ect did well out of it though. Its mainly small businesses that go, and its usually a 6.30am start, have breakfast, then the new member can stand up and do a presentation and explain what he or she does.
Go along for the first one and see what you think, you will be able to see from the first morning if its going to be worth it.