I'm still in the Enstrom 480 group to which Joel refers. I have been involved in both fixed wing and heli groups now for over 15 years. If you get the right people and a rulebook is agreed from the start they do work very well. Every now and then you will have an unexpected bill, but at least its split five ways. In practice it costs us all an extra £1000-£2000 per year. We are negotiating at the moment to group an MD500.