This is a pretty generic episode for the series, one made less significant as the franchise expanded (the Voyager entry "Tsunkatse," for instance, is better, as are numerous other examples; although it could be done far worse, such as "Code of Honor" from Next Generation). Kirk and a few others are taken prisoner on an alien world and forced to become combatants in an arena. (Which is completely different from, say, "Arena.")
|via Trek Core|
The main draw is the latest disagreement between Spock and McCoy as to how to proceed. It'd been done before, and would be done again, at its best, in "The Tholian Web" next season, but the fact of its recurrence is the best way to recommend watching the episode. Otherwise take it or leave it. In some ways, an episode you really ought to just skip if you really want to.
There's an Andorian in there, if you want to watch for that.
four quarter analysis
franchise * series * essential * character