Richard Benjamin and the other guys are out to relax and have a grand time at the theme park, outdrawing the robots, joking around in the saloon, and yes, and having sex with some of the female robots, in general, acting out their male fantasies. The next day, however, one of the robots shoots one of the men dead, the revolt of the machines. The one bad robot is played well by Yul Brynner. With a subtext about our exploitation of slaves and coolies, Westworld is a worthwhile watch for action and some suspense. They also made a sequel a few years later, which I also enjoyed called Futureworld (which was not by Crichton). There was also a short lived TV series, Beyond Westworld (1980), which ran only three episodes, with two further episodes made that were unaired.
At any rate the new HBO series sounds promising. Although I don't have HBO, and will have to wait for the series on DVD, I hope it does well. Read about it here.