I left OATS 5 weeks ago after 15 months. I did not ever have any problem with loosing slots to the sponsored students. I know that it has gone on in the past but if you take a grip of your own training and push yourself it is not a problem!
One MAJOR thing that OATS has done for me is they have been instrumental in getting me a job! I left 5 weeks ago and have been offered a jet job, what more can I say.