PP
I am not against OAT if I had the chance again I would have gone there. I advise people, who ask me, that if they can afford it to go there. However I have worked at big COM schools and believe there is a too structured approach. Logging P1 in a twin while an instructor sits next to you means you always have a back up which you do not have with true P1. Many of my friends and colleagues who went to OATetc said that when they went into GA they were not comfortable with the different environment. These schools did not set up to provide GA pilots they are trying to provide low hour pilots to airlines a job they do very well. I do believe that as a rule many GA operators do not favour 509ers unless they have other experience and look at the air taxi companies in the UK you will see this has been the case (even before 750hrs came in). In your case I have no doubt you where a very good air taxi pilot but in my experience a self-improver pilot can initially be better suited to GA than 509. There are bad pilots coming out of both systems so I again accept this is a generalisation but I can only go by my experience.
AD