I am not sure that the decision to drop UA is such a great loss, particularly given UA's precarious financial condition. AFAIK, you can still transfer CO miles into Amtrak, which can then be used for rooms at Hilton, Marriot and Ritz Carlton (mmmm!) Given the trends in airfares and room rates ^ this may prove to be a blessing except to those (like me) who needed a few thousand miles to top off a pricey UA award ticket.