AOPA UK 'represents' a constituency of less than 28,000 PPLs (not including balloonists)and I think their membership is around the 3000 mark. That equates to a subscribtion revenue of only, lets say, £175,000. From that they must fund their staff, premises etc etc. They may not appear to do much but they are very active where it matters. (How effective their activity is I leave for others to judge). If more pilots were members perhaps they might be able to afford to do more. In the meantime they are the de-facto organisation defending and promoting GA (along with the PFA) and have the ear of the regulators. At the end of the day it isn't much money we are talking about so I'd earnestly ask you to consider joining both AOPA and PFA.