A few more positives for the United card. I value zone 2 boarding since I always have a carry on and typically United's overhead bins fill up. Also I don't have exact proof to back this up but I think you get higher on the priority list if you have the United card (recently flights were cancelled and I was put on standby for the last flight of the day out and I was #3 out of 76 people on standby and actually got a seat instead of having to sleep in Chicago).