Please don't take offence if I'm stating the obvious, but isn't the main point of a union (the clue's in the name) to enable pilots to form a cohesive body which is able to take agreed action on behalf of the individual members. It never ceases to amaze me how many of us do management's work for them, by separating ourselves from our colleagues because we think we have a better idea of how to be represented or because of some past grudge against BALPA.
I'll be the first to admit that BALPA is not perfect, just as any alternative is not perfect. But my point is that it's the unity of belonging to one association that is far more valuable than any perceived flaws in that organisation. If we all belong to different entities, or none at all, then we really don't have much collective influence do we? Or maybe I'm missing something.