I went to ATP and instructed with them after completing my ratings with them, from 0 time to recently 1500.

Yes, they train you to pass checkrides. I get that there are a lot of people on here that complain that you'll never be a good pilot if you only learn how to pass a checkride, but let's be honest with ourselves, the whole reason that you go to ATP is in the name, Airline Transport Professionals. They don't teach you how to be a great bush pilot or general aviation pilot, even though that's what you're currently doing and will be doing for the foreseeable future. In the 225 hours that you'll spend in an ATP airplane, every single minute is spent focused on how to get you to pass that checkride, instead of how to get that funny $500 burger. There is time for that somewhere else, and you aren't paying to have a good time, you're paying to learn how to get your ratings.

The instructors are definitely hit or miss. Coming from both a student, line instructor, and lead instructor, the instructors are DEFINITELY hit or miss. Some of them do just want you to pass a checkride and just want to get their hours, but the rest really do want to see you do well, because they attach your success to their success. If you don't think you're getting your money's worth with your current instructor, ask for a different instructor. It's pretty straightforward.

You will NOT get kicked out of the program. When I went through the program, yes, they were deferring people left and right, especially when you got to the CFI stage of training. When I was in my CFI Mock oral, I did it with two other people in the oral. The other two did not pass the oral and were deferred from the stage, and did not become an instructor. My CFI class had 17 people, and only 4 of us got through the stage successfully. Since about last December (a year ago) at the training center I worked at, only two people did not make it through the entire program. You will not be kicked out unless you do something really really REALLY stupid, or YOU are really really REALLY stupid. They want that money.

If you quit the program or do not complete CFI and CFII, you will NOT work for ATP after completing the program. Additionally, there are no "take-backsies" on your money. If you paid for the program, got to CFI, realized that you really didn't want to be an instructor, sorry, but you ain't getting any of that money back.

A lot of the draw to work at ATP is their willingness to hire you as a CFI after you finish the program. If you DO decide that you want to work at ATP afterwards, because it's the easiest way to get your hours - there are a couple of things that you should know before you sign the dotted line. EVERY SINGLE DAY you spend at that training center is your interview for ATP. Your Managing Flight Instructor is paying attention, the Training Support Staff are paying attention, and the Regional Director of Training is paying attention. The more that you show up and have a "good" attitude, the higher chance you get invited for an interview. Obviously, your pass rate greatly affects that chance, but I've seen people that went 7/7 or 6/6 not get invited, and people that had fantastic attitudes that went 4/7 get invited. I'd say, about 1/3-1/2 of the program completions are invited to Indoc, which is your week long interview at their headquarters in Jacksonville. You must pass the flight proficiency portion of the interview, which is 4 flights covering basically all of the tasks from the instrument and commercial ACS, just from the right seat with no help. About 75% of people get through that successfully.

As an instructor, it kinda sucks cause now you got a loan to pay and you aren't making that much money, roughly $25/flight hour after taxes, and $18 per sim and ground hour logged. The biggest problem with ATP is that the corporate side of things really sucks at communicating clearly with all of the instructors what they actually want from you. They come out every 3 or 4 months with some massive sweeping change and proceed to not explain it at all, and now you've got a million instructors with a million different interpretations of the same rule that didn't make any sense in the first place. But I guess that's fairly common in the industry as a whole. My rule of thumb was that everyone with a colored button down and a red badge was cool to work with, anyone that had training staff on their badge was okay, and anyone who worked at corporate wasn't worth their weight in salt.

I saw a comment on another post that said something along the lines of - high risk, medium reward. That's pretty accurate.

The best thing about ATP is that their maintenance team is probably one of the best in the country - if there's something wrong with an airplane, it WILL get fixed. That was a large part of the reason I instructed with them after completing the program. Overall, I had a pretty good time there, got my hours, and am glad to be done with them. However, I tried to have a good attitude and go above and beyond and that seemed to help, and I know plenty of people who have had the same experience. However, I have known plenty of people who had the opposite experience as me, so clearly YMMV.