The good, the bad and the idiotic (SPOILERS)
Despite the contrived plot, based on Kurosawa's "Seven Samurai" (1954), you can't beat the lusty score, the superlative locations and the excellent main cast (the villagers, by contrast, are mostly weak). Unfortunately, the movie's ruined by hokey script flaws. For instance, Chico (Buchholz) is able to effortlessly infiltrate Calvera's bandits, utterly fooling them, even though there were only 32 of them by this point (rolling my eyes). Even if Calvera & his brigands failed to make out Chico's face, which is a big IF, his dialogue & accent would've given him away. Keep in mind that he was just an unseasoned teen.
Another prime example is the village leaders' sudden cowardly turnaround (i.e. betrayal), which totally contradicts their earlier resolve (!). Yes, I realize they learned that the bandits weren't run off and that they were going to return to the village out of desperation, but there were only like 30-32 bandits left at this juncture and the combined forces of the seven gunmen and the fighting villagers now had the opportunity to annihilate the thugs for good. The sad thing is that both of these script hitches could've easily been fixed, but this kind of lame writing reflects too many Westerns before the 60s when the modern Western came to the fore with "One-Eyed Jacks" (1961), "Hombre" (1967) and "Butch Cassidy and the Sundance Kid" (1969).