I didn't train with ATP from the get-go, but did their two-week CFI course and was hired on as an instructor...I can tell you that what I saw from the majority of their instructors was almost shocking. Not surprising only because they train to the test and in-breed the majority of their IP's. Also, they were never particularly pleasant to deal with, BUT they delivered. I was notified of an interview with my first Airline after just a few weeks as a CFI with them, hired and in class a week later. PM me if you'd like, but whatever you do, good luck!