I've not been to OATS, so cannot comment on the course etc. However, I considered them very carefully before electing to save a lot of money by training elsewhere. One of the things that swayed my judgement was the lack of any evidence that OATS training was better than the alternatives (indeed, perhaps on the flight as opposed to theory training side, some evidence to the contrary), and lack of any evidence that paying the extra would secure better or more rapid employment upon graduation, when compared to other reputable training establishments.
My own assessment, for what it is worth, is that
you are the vital ingredient, not the training establishment. The only way of gaining an advantage is to be selected for the CTC ATP scheme. However, I believe that you are already outside the maximum age limit (worth checking with
www.ctcaviation.com to find out that from the horses mouth).
One tip to save money on the OATS course is to decline to do the MCC element. If you are lucky enough to get onto the ATP scheme, you will not need the OATS MCC. Many type rating courses include MCC, and even if you do subsequently find out that you need it, you can get a much cheaper tick in the box by going elsewhere than OATS. The saving might be much better spent on paying to keep current while looking for a job.
Whatever you decide, do not burn your bridges, especially as a career changer. Meet a lot of people who have been there and done it; and ask them about people they trained with who did not make it as well.
Good luck
