I've heard the same thing.
It is very hard and very unlikely that anyone from the Ready Reserve program gets promoted to the DL mainline system. All I know (from my nephew) that sometimes (if you're lucky) that you will have a set schedule and set hours. But basically, you are a "on-call" employee when needed. (at my airline, it is called "vacation relief" or "outage relief"), where you are replacing someone that is not available to work. That is a regular bid line with a set amount of days (part & full time)
Personally, I do not understand the logic (otherwise "saving" money) of doing this when you can have a part-time employee doing the same work. In this line of work, some people like working part-time. If you are going to stick it out with DL, I think it should be a 6 month probationary period, and then promote you full-time into the DL system with full benefits and other stuff.
Can someone tell me how the "Ready Reserve" program came about?
Also, why did DL start Delta Global in the first place?
I can see some logic in that if they are trying to get ground contracts OUTSIDE the Delta system, but having it's own company bidding for work inside the DL system makes no sense to me at all. With the NW stations coming into play, I think that it should be more work for more people either part-time or full time. I don't know what the IAM contract states on part-time workers, but I do know that the TWU contract treats part-time workers differently. I think that BOTH part-time and full-time should be treated the same with all benefits (except a different percentage of dues paid - according to how much is being made.) But I digress..
Sorry about going off tangent.
Good luck in your job with DL. I hope that you will make mainline if you want it.