PBS is not the issue, but the language and rules that comes with it. I would be more focus on what PBS will do with vacation or training events. Would it add trips around vacation, or can you create a conflict because PBS doesn't look at your vacation. Where you can take 1 week and turn it into 2 weeks off like line bidding. This goes for training events too. If you're worried about the lack of open time with PBS, why not negotiate for a percentage of open time, so it creates less lines (if that's what you're worried about). PBS is not the end of the world but it can be great if it comes with great language and rules. This is why PBS is different from one airline and another.