My SO is an FA. Unless your buddy is super senior and you value saving a few hundred bucks over your time/sanity don't do it. There's no benefit unless you have nowhere to be and the price difference is big enough that you wouldn't be able to go otherwise.

We've been together over 7yrs and I've always just bought the ticket. It's good enough if she can get somewhere w/ me. I've even considered using miles so she doesn't have to go standby and her priority is still far higher than buddy passes. I used one once for a routine weekend trip to DCA while I was between jobs and due to a single AM cancellation, we wound up spending the entire day at the airport and still had to buy a hotel room to spend the night (which cost more than the ticket). Her friend used one, got stuck in Germany for a week and had the gall to write a negative review of it to the local paper.