pretty good, I enjoyed it immensely for what it was. Some quick thoughts:

I was halfway sure someone would come up to Jake at the end with another alien wristband saying hey took it off from this dead alien, want another?

Nothing was too surprising in terms of twists, the aliens were well rendered and their motives fit well for the Western setting.

Ford feels slightly wasted in this.

A bit of Total Recall/War of the Worlds/Predator for our alien folk.

Between this and Outlander I think Outlander was the superior film. Each of their approach is different, where C&A is about a scout and stealing supplies for a possible invasion, Outlander is a bughunt movie with an humanlike alien hunter. Both of course have to be creative in dealing with their foes. Both feature recognizable gruff guys as secondary characters (Outlander had Ron Pearlman, C&A had Clancy Brown).

Those flyers seemed afwully small to catch so many people.