I recently interviewed for Flexjet. As far as the sim ride goes, you can expect a normal takeoff and some basic attitude instrument flying. Climbs, turns and descents with speed changes. Then expect a turn to a VOR and given holding instructions. You may or may not enter the hold depending on whether or not you described the proper entry etc. After that, vectors for raw data ILS to full stop. Sim is then reset, takeoff again with a V1 cut runway heading to 3000. That is it in a nutshell. We had one of their pilots act as PNF since they know you won't know the airplane. Ask for anything you need. Sit in whichever seat you are most comfortable. Your choice.
As far as the interview itself, it was a panel interview. I had 5 people sitting in for mine at various levels of management. Very straightforward. Standard HR interview questions. Nothing technical. You will also be required to fill out a behavior assessment prior to your interview date. This is completed online.
My interview may have been different than the "off the street" guys. I was one on furlough who was called back. Hope this helps a little. Good luck!