I left BALPA because I thought they could not provide value for money. The CC reps gave up the job in our company because they had so little support from BALPA against a company that rode rough shod over the supposed agreement between the union and themselves. Not only that, but BALPA did nothing to notify the members, and we had no CC for 6 months.
More generally, I can not believe that they have let the industry get away with being allowed to make pilots pay for type-ratings with absolutely no comment what so ever. At the very least it could have been allowed to support the industry through the lean periods, but now that companies are really having to work at recruitment (ie demand out strips supply), it sstill goes on, and has become common practice in all but a handful of airlines.
If you want a union with a pilot bias, try the IPF: if not, TGWU. Save yourself a bomb every year.