In reply to lex:
I use club direct, have been for last 8 years for climbing trips abroad, never had to claim from them.
Used BMC before that and had a big claim for hospitalisation in Chamonix and being flown home, they took ages to pay and getting the money was a real hassle. They were underwritten at the time by General Accident so it wasn't the BMC's fault its just insurance companies don't like paying out!
I will always go for the cheaper option these days and take the risk of a long drawn out argument about paying out if the worst happens, as in my experience it still happens if you pay more.