It's good that you're doing a lot of research, I can only speak for Horizon but I know the Compass contracts can be pulled just as fast as they lost MSP a while back. You really need a crystal ball to try and predict what is going to happen in the industry. I certainly hope it doesn't happen to them.

As for Horizon, if you have a jet class (in writing) you won't have a bad experience. A lot of the griping and misery we display here is caused directly by the plane and schedules we're flying, and if you get the jet you will essentially be free from all of that BS (6 leg days, cancellations, mx, winter etc).

As far as the trip rigs go we are paid block or better, duty time, or trip time away from base.

Block is paid 1:1
Duty time is paid 2:1 (say you have 4 hours of block but 10 hours of duty time...since your duty time was higher than your block you will be paid at duty time divided by 2, so 5 hours in this case.
Trip time is paid 4:1. So if you have low block or duty time days, if the time away from base is higher than both block or duty time, (say 76 hours) it would be paid 76/4 or 19 hours for the trip minimum.

As far as job security goes I would say Horizon is in a better place right now unless compass wins another multi year extension. We aren't going anywhere.

The transition from jet to Q captain would be tough but it's not impossible. It wouldn't stop me from picking the jet.