Originally Posted by
mauld
Oh no! Don't let channa see this post--- a UA 1K generally praising CO and finding fault with UA. This close to the holiday's, we wouldn't want to risk sending him into shock

Nothing new here. With UA's *net blocking, if you get hit with it, reward redemption can be a challenge.
The minute CO joined *A with no blocking, CO's miles became easier to use than UA's. I think that's well documented here on FT.
Not to mention, UA has some arcane rules on their awards -- no mix/match of cabins or saver/standard, and UA does not allow changes to *A awards once travel has begun (unless you're switching to fly a UA segment). CO is also more generous with allowing a stopover and an open jaw, whereas UA allows only one or the other.
The one thing UA does better policy-wise is that there's no close-in fee for awards for anyone. CO only waives this for Plats (effective today). But that's somewhat offset because CO allows everyone to change for free, provided you do it 21+ days out and keep the same O/D. UA goes all arcane again, and requires that you fly the same carriers along the same route, though there is no 21-day requirement, but you could get hit with the no changes to *A carrier flights once travel has begun rule.