WELL worth it, if you can afford the travel costs.
Living in North Somerset it's a fair old expensive trek for me, but I did go to one a few years ago (when I hadn't even got back into fishing yet, during a long lay-off) as I happened to be in the vicinity for a work meeting, so hotel and travel had already been taken care of.
As others have said, it's a great day out. The one I went to had Tony Miles (RIP), Tref West, Duncan Charman, Bob Roberts, Steve Pope and a few younger guys who I'm sure were (are) a big deal, but as I'd been away from it for so long I didn't recognise them. I only had a chance to speak to Steve Pope (lovely lovely guy) and Bob Roberts (great info, just don't mention politics - let's just say he has..."interesting" views...), but the others did some really interesting talks.
There was also plenty of stuff there to buy, and a lot of offers too. One of the bait companies (I think it was Dynamite, but can't remember for sure) had a particularly large presence, and they were almost giving a lot of their stuff away it was so ridiculously priced.
I'd love to go again, but I'm either looking at 3 hours each way in the car plus petrol, or 4 hours on four trains each way at over £200 for the round trip ("USE PUBLIC TRANSPORT - IT'S QUICK, CHEAP AND AMAZING!!!!!").