I'll jump to CO only if the following three statements are proved to be true.
(1) 100% RDM & EQM on any paid fare on UA & US.
(2) Earning on other partners is satisfactory (Not sth like Y, B fares only).
(3) I am, at least, allowed to purchase an annual E+ option on UA and credit the miles to CO, if not having free E+ access.
If so, CO's program will be nearly perfect.