First thing that jumped out at me there was that no accomodation is included. So for 2.5-3 years, you're effectively working for nothing.... and having to pay for your own accom/meals etc.
With regard to Rainbow Air, I've seen the name about PPRuNe before - they provide training aircraft for other schools at Long Beach I think.
This thread may also be of interest. I believe the providers of this course, Angel City Flyers, use Rainbow aircraft for some of their training.