In reply to The Great Pretender:
Like any organisation, the more you put in the more you get out of it. For me, the advantages are qualitative and social rather than in terms of financial benefits.
The lectures are excellent, and you often get to see these before they are presented elsewhere, and in a more friendly informal setting. I value the library, archive and photo library as part of our climbing heritage, even though I haven't made much use of them myself.
I also get invited on a lot of trips and have made many friends and contacts, and the Alps trip is always good. I've sometimes turned up on this with no partner and still found plenty of people to climb with.
One thing I have found is that because I mix with people who travel, climb and write a lot I end up doing the same without having to think about it and it's extending me as a person.
I've met some of the most interesting people just through chatting to strangers at the club bar. An anonymous looking older gent quite often turns out to be a mountaineering legend from yesteryear, with a wealth of interesting tales to tell.