Whereas some episodes in season three are at least watchable for their camp quality, this episode is quite painful to sit through.
Basically, there are some major plot holes in this story: 1) In a planet so crowded, how could room be made for an exact replica of the Enterprise? 2) How did they get the specs for the Enterprise? I'm sure the Romulans or Klingons would like to know. 3) How did Kirk get fooled so easily? Even a replica of the Enterprise cannot feel or look exactly the same as the real thing - he would have known right away that it was fake. 4) Since when does Kirk beam-down without a communicator? 5) I'm sure there are easier ways to get people sick than kidnapping someone with a rare disease - and why didn't they just make their own "carriers" from the start? 6) Even if Kirk fell in love with Odona (as was the plan to make him voluntarily stay), if she had died as planned then there's not much reason for him to stick around, is there?
Unfortunately, this episode is not even entertaining to watch, save for a few interesting camera shots (like the view from the bridge at the beginning and the low angle shot of Kirk through the glass table). They should have thrown this script out...