I wouldn't have gone to Luis's first UK meet had I not been in London anyway. Thereafter, I've endured the 7-hour coach journey for each one and they've all been worth it.
I was fairly pumped to meet a few folk I respected but generally, the 'meets' are just about going out, having fun, getting to know some new folk/make new friends and have a laugh.
I think you get the most out of them if you're an independent adult but the younger folk who had guardians at the London meet seemed like they were having fun.
Like someone said - it's just another social situation. Citricsquid (who still owes me a picture) was a bit quiet and I wasn't sure if he was having a good time or not - glad to hear you were, Sam! If you feel anxious about meeting folk, well - that's maybe something you need to get over in any case and meeting a bunch of fellow geeks who'll probably be happy to converse about games/animation/nerdy things is a good environment for that. Conversely, if you enjoy talking to random strangers, it's just a place where you know everyone's on the same wavelength and will be approachable.
I totally recommend it. Even if you rarely go on the BBS.