Apologies for wading into the "IT union" side discussion, but I have to agree that a union is not really an ideal fit in general for developers and DBAs.

And its certainly not something I'd be tempted to do just to score some more vacation time.

I think I'd dislike the union dues, stress of collective bargaining, lack of accountability, and primacy of seniority relative to competence more than I'd like the extra vacation days. Not to mention the potential negative impact on company performance and adaptability.

Unions have their place. There are some jobs and industries where without them, employees could (and/or) have been squeezed to barely liveable conditions without them. But they are not a good fit everywhere, not a good solution to every "my pay/benefits suck" problem.