Surgery last is the most accurate protocol, surgery first is the fastest protocol. I was set on surgery first from beginning and was told I would probably need some months decompensation, but surgery early would be possible. But after some discussions and me asking all my questions, the response was something like "The way you look at your face, you should definitely go for surgery last".
I won't say all cases, but many cases can be handled with surgery first or early with todays technology. You can do 3 piece lefort etc and get the bite to fit. But best outcome is always with surgery last, as that involves no guessing of what can be achieved in the postoperative orthodontics, and the surgical intervention can maybe also be handled with less invasive procedures and the surgeon don't have to make tradeoffs because the bite is not properly prepared.
As my surgeon explained it, it's really up to the orthodontist when the surgery can be done. If the ortodontist take the models and put them in the anticipated class I relation and figure it's a suficient starting point for the posoperative orthodontic treatment, then it's a go. That's really all that surgery first is.