I'll try to keep my thumbs-up comments (not my trademark obviously) to a minimum. Much like the advertising that has kept a good deal of what you get from this film under wraps, I'll try to do the same so that you'll go see for yourself. Better than some of the other comic book films out there. Sounds like faint praise, considering X-Men First Class (the best of the series), is the only other film that would be fun on home video/cable to see again.
A good blockbuster, but a liking of Westerns helps. Not mandatory, but very helpful. Cowboys and Aliens is a Western first and an action film a close second, with just a few touches of sci-fi. Some of you might say "there's just 1 thing I had a problem with" with the story. Shut it; you get just the info needed to let the story happen without insulting anybody's intelligence. Besides you're paying to seeing something called Cowboys and Aliens, were you expecting Allen or Malick? A summer blockbuster need not fall into these categories to be fun. Though if you don't know the actors playing any of the supporting characters, you won't care what he/she does, or what happens to them. I cared about say, Clancy Brown or Sam Rockwell or The Shield's Walton Goggins, because I remember them from other performances, they got the chance to provide just enough atmosphere and could raise their status from one-dimensional to two-dimensional. But like I wrote before, the bare minimum info about people here. Enough to have a rooting interest against an enemy that has obvious technical advantages, and just enough arrogance to underestimate what they're dealing with.
I'm grateful this isn't played for camp, and I'm grateful to director Jon Favreau maintains high-ish emotional stakes, and only indulges a few scattered moments of humor here and there. I'm also grateful that he maintain his ideal of Westerns being only only shot in film and (more important to me), he avoided shooting or converting this in 3-D. It's hard enough to maintain an Unforgiven/Searchers style of Western, with an Independence Day/ War of the Worlds of 1953 aesthetic, without the studio threat of either shooting in a style you don't want forced on you, or be involved in a crap conversion style. Thank you Mr. Favreau. Kudos as well to visual effects that blend pretty well. The CGI creatures themselves, see for yourself.
Besides, how can you not have fun with the two leads? Don't worry, the idea of Bond versus Solo/Indy goes away quickly, and we can settle down and get into who they're playing. Daniel Craig plays a character whose DNA seems to be some Magnificent Seven/ Butch and Sundance hybrid, and Harrison Ford as the sort of man who would have been a good fit in the world of Unforgiven. Both may be good men doing not so good things, but there's no point in staying the course, when they face a credible threat bigger than both of them. So just sit back and enjoy the 2 hours of moderately dark fun in an air-conditioned theater.