I am also moving from CO. I have been OnePass Elite since 1996, but I've grown frustrated with the EUA games, the problems with redeeming miles, the uncaring attitude of customer care, and (the final straw) the new elite qualification rules.
UA comped me to Premier Exec, and I have already purchased over $1500 in travel on UA for the first couple of months of 2004.
I have a few more trips on CO, but the last one ends Dec 16. After that, the only time CO will see me is when I use my OnePass miles.