I only have personal experience with the 9E training department, but it is excellent. (Since the mergers, that is.)

The 9E contract treats sim instructors better than any other special assignment workgroup, and the perks they get are better than some mainline carriers, though the scheduling does generate some complaints. This means hiring for these positions is competitive and you generally get sharp, well motivated instructors who want to be there. There are some phenomenal instructors there who are both gifted teachers and very knowledgeable CRJ pilots. 9E is fortunate many of them chose to stick around rather than flow to DL.

The company gives new hires a few extra sims when needed without significant pushback. They know how to get a 975 hr 172 CFI to proficiency on a CRJ-200.

In indoc there are a few 80% to pass closed book tests and if you fail those too many times you may not have a long future at 9E, but those who apply themselves will be fine even if there is some struggle.

I’ve heard some things about other regional training departments that made me feel fortunate to have gone thru 9E’s program.