I went to OAT and have no complaints. There not perfect, but who is. Once graduated from OAT I had three interviews thanks to their recommendations. I also had another 2 interviews which I got off my own back, but one of those I only got because I had OAT on my CV. I was on a double course that graduated in March this year and out of the 44 people in the course all but 4 are now employed for major airlines. 2 out of those 4 not employed are in hold pools waiting for start dates.
This is just my experience of OAT. I enjoyed my time their and due to having good reports and good exam marks I was recommended to some of the best airlines (BA,BMI) It was my own fault that I managed to muck up the interviews!