I thought I already posted this but now I see that my post and the one before mine are both gone. Anyway, 1P also gets 3 70lb bags instead of 2 50lb bags as well as higher upgrade and standby priority.

So last Sunday night at BOS, I discovered that having a priority tag means being the last one to find your bags.... UA 618 -- Announced that 618 bags were on 1, all others were on 2. I noticed that the first bags out did not have priority tags. In fact, none had priority tags. I suppose that was a clue but I was tired... After all the bags were out, there were a bunch of us still waiting. Someone finally realized they were on 2 with the hundreds of other bags from SFO & IAD. They had put all the priority bags on 2 but didn't bother to let anyone know. So much for getting out faster!