At TWA, we used AdOpt until Dec. of last year. Most people were wild about it. I was less than enthused.
It really does reduce the number of crew members needed to run the operation. You can avoid month-end conflicts caused by sequence bidding. It can avoid training and vacation conflicts. I would imagine you can program the system to ignore certain conflicts if the contract mandates it.
You bid for your preferences using a point system. If you want a certain day off, preference that day off at 1000 points. Great if you only have one occurance. If there are more occurances, the points are multiplied by the number of occurances. Say you bid 500 points to get a certain day off. You also bid 101 points to fly a certain trip. If you get 5 of those trips, you could be working on the day you wanted off--505 points(5 x 101) outvotes 500.
I got screwed so many times in the 3-4 years of using "Pref bidding" as we called it, I lost count. My contention is that you shouldn't have to take a college level course to learn how to bid.
There was another system we tried that, although I didn't use it during the trial period, I think it was easier to understand. It took preferences in order. What you wanted most, you put first.
So simple even I could do it.
AdOpt also leaves a lot of room for mischief by unscrupulous management dicking around with the parameters. Not that I'm paranoid, though...
TC