I went through ATP and it did what they said it would. Got me from 4 hours TT to 250 in ~7 months.
Not sure if you have thought about this yet, but there are schools such as Utah Valley, or Riddle where you can use your ratings you already have towards a degree. So if you speed through ATP to get your ratings, then instruct to get to a regional. You could then do college online while at the regional and since you have your ATP and all those ratings you get almost a year and a half of credits towards your 4 year degree. Just another way of saving a little bit of money.