I've worked under PBS, and it wasn't the end of the world. But, we didn't have the vacation system that we have at FDX. It would be a real quality of life issue to switch to PBS for that reason alone.
Again, the goal of PBS is to optimize our schedules. I've seen enough optimization lately, our schedules are definitely getting worse. I wouldn't vote for a contract that includes a PBS.
For those that haven't used one, it simply takes all of the individual pairings and instead of the company and SIG making the monthly lines, you make your own line. I've had very good schedules, some not so good. I found that while seniority is important, a good knowledge of the software is also key to getting a good schedule. Of course, this system "bids around" your vacation and training. This leads to optimization, and makes us work more. PBS generally uses a monthly cap, which is another thing I am not in favor of. I like being able to work slow months in the summer (kids out of school) and pick it up more in the winter. .