From the operational perspective, the Western/Delta merger was the best executed merger in the airline industry. There was one reason: Western employees were paid less than Delta and Delta brought them up to their payscale. Voila, everyone at Western got a raise (or at least were neutral) and were very happy to work for Delta.

In addition, since their route systems did not overlap in a large way, there wasn't the employee contention like the RC/NW merger at MSP and DTW (had employee contention for years and years).