I really like this film a lot. I'm a big fan of Sterling Hayden, Nancy Gates, and Frank Sinatra.
There's no arguing that it could have been better. Some actors are miscast (would have preferred a more seasoned actor play Slim...such as Martin Landau), but overall, it's a fun film to watch.
In my opinion, Frank Sinatra was a much better "bad guy" actor than he ever was playing "good guys". He's the best thing about this film...sinister, self-serving, and cold-blooded. A great performance!
Like others have said, it's the "fifties" sets and costumes that make this really interesting. Had the director spent a little more time in choosing the right weapons, and tightened up the secondary casting, it probably would have fared better.
If you've never seen it, do yourself a favor. It's a hoot, warts and all.
Johnboy