If it came along, yea, a union job would be great. The point is, from a macro-economic point of view, it doesn't come around for enough people. If one person takes a unionized job, other people will not receive a job precisely because he is getting paid more than market forces dictate. And that is my point, since when is it a left wing ideal to screw the many so that the few may succeed?
I got really pissed off with this after going to France. The entire country thinks of itself as socialist, but "socialism" has become an excuse to just freeze the poorest residents, mainly disadvantaged immigrants, out of the economy. So, a French laborer is getting overpaid while immigrants are starving in slums. Unions are a monopoly on labor, and the poor almost always loose out the most from monopolies.