It appears that I am not alone. After my recent post, Loyalty Programs, Status, and Mileage Plus Disappointment, I've began hearing commentary from friends and colleagues who have essentially removed United from their preferred airlines list. Again, these are people who have been Premier or Premier Exec, and now essentially preferentially look for other airlines. Anecdotes that I've heard even include paying for upgrades to Economy Plus, then expensing the upgrade separately.
I can also tell you that, for the majority of the coast-to-coast round trip business travelers that I've spoken with, JetBlue and Virgin America are their preferred carriers. Even with some of the frequent international travelers, they will opt for JetBlue or Virgin America domestically and ignore any mileage incentive.