Greetings, Falconjet. Here's my opinion on how it works at AWA. I have mixed emotions regarding PBS. On paper, I really like the idea. The major caveat seems to be whether you're a wizard with computer/math logic (and's, or's, if's, but's, etc.). Seniority is also supposed to play a huge role. I'm very junior in seat/equip., so I can fill out my bid with my dreams, and can pretty much count on not getting what I want. However, I've only been able to hold a line three bids. Of all the pairings I was assigned those three bids, only two really "flew in the face" of my "avoid" bids. So, I had a roughly 85% success rate in not getting what I really don't like, and a 23% success on getting overnights I really wanted. Being back on reserve, I'll stand by my opinion that it's a relatively useless program for reserve bidding.
Many of our guys don't like the math involved with PBS -- if there is a particular trip you want, you have to be careful that all your other bids don't mathematically cancel out your "score" for the trip you want. (You aren't really awarded a traditional line -- you're awarded trips that get thrown together in accordance with your mathematical requests that ultimately comprise your line.)
I guess, bottom line: if you're senior and understand the math and scoring "logic," it'll work out great for you. If you're junior and/or don't play the "and-or-if-but" game very well, you'll be very disappointed. If you get PBS, whatever you do, make sure you've got a couple genius types on your PBS committee who can help "build" your bid.
I could go on forever, but this is pretty much the gist of my experience with the program. "You're mileage may vary." Cheers!