Well I,m in BASSA and I believe for us it,s united we stand devided we fall,we have just over 10,000 members all BA,and are linked to the TGWU.CC89 have about 6000 but they are diluted into small groups belonging to the other outfits ie virgin etc, however there is strong opposition to union membership by some of these airlines so CC89 have done well to get some form of recognition.
However memership is an individual choice, but should you get on the wrong end of your company for any reason, its always good to have somebody who can give you advice when you,re backed into a corner.