Just completing my IAD-LAX-SEA-ORD-IAD trip for a Change of Command in Bremerton. I had significant problems on my flight out IAD-LAX-SEA as I was initially supposed to travel from BWI-EWR-SEA but due to weather I had to change flights. The most annoying thing was this was on 1 March and before the integration and my OnePass # remained in the reservation so I wasn't able to UDU from IAD-LAX. When I got to LAX a much better gate agent cleaned-up the record.
Today I'm travelling back from SEA-ORD-IAD. All is well. Lines were a little long at the SEA check-in area but no major complaints that I heard. I had a minor issue where I had a seat assignment for my second flight online 7D but it wouldn't print on the boarding pass when I checked-in. I used a customer service rep and they fixed it no problems.
All in all I feared the integration would go poorly but there was clearly very detailed and good prep for this integration. So far, no major problems and my flights are all on-time.