If history be the judge, neither alpa nor teamsters are the best. Both tend to look after their national organizations first, ensuring their survival even if it comes on the backs of their members.
Pilots probably need a union given modern management tendencies. However, that union should look after its members first and its bureaucracy should support the members, not vice versa. ANY union can provide competent legal and medical advice. Surely nobody is trying to say that the pilots at American, Southwest or UPS are somehow being disadvantaged because they are not alpa. Shoot, they make a LOT more money than alpa carriers and have lower dues because they don't have the bloated staff. When staffers in Washington are making more than 757 captains who pay their salaries, something is out of wack.
The last emperor of China fired all the eunichs. He discovered that he had hundreds of eunichs on the payroll, but that they were not serving him, they were serving the eunich bureaucracy.
The facts seem to support that those pilots with 'in-house' unions are doing better than either alpa or teamster members.