In a previous life, I worked for an FAR Part 121 cargo carrier. Initially, they were represented by the Airline Division of the Teamsters (IBT) and frankly, I thought it was a waste of dues money. In my view, the IBT Airline Division did absolutely NOTHING for the membership; didn't seem to care about pilot issues and their only focus was the collection of monthly dues.
As for ALPA, I believe they accomplished a lot for the pilot profession initially; however, they never kept their eye on the ball and in the past years became a political organization with an emphasis on advancing the agenda of the union leadership group in Washington. l think the pilot group at my former employer would be better served by taking their union in house and let ALPO die a natural death.