I have been using United on a regular basis out of EWR. They used to be very good as far as showing up at the gate and get you on. After the merger, a lot of gate agent don't know what to do with you. They don't know if they have to list you as a jumpseater or nonrev. I almost got left behind twice.
The ALPA website still say that you are just supposed to show up at the gate.
It is a lot easier coming back, although you have to show up at least 90min. prior.