The people I know at F9 are for the most part pretty happy. They are also pilots and attached to DEN. That being said, I'm not a fan of DEN and will hopefully be out soon. As an engineer, have you considered FedEx? I'm currently looking at an ad in the back of AW&ST for engineering jobs at FedEx. To apply, visit fedexairops.com. It would pay more and be more stable than F9 if nothing else. Hope it helps.