Ive been here a little less than a year so my info may be a bit dated so take from it what you will.
During training, my entire class was listed as ACY based. Training was around two months and towards the end of training (OE), the senior people in class were awarded their first choice (FLL, DFW) which seem to be the most senior for FOs. There was one guy who bid ORD and was awarded ORD after OE.
I hope this helps.