This episode requires a leap of faith from the viewer: we have to believe that the power surge that causes Data's amnesia blocks his memory of who he is and where he's from, selectively allows him to function, retain the ability to communicate, read the English word "radioactive" off his container but forget what the word means, and have enough skills to cure radioactive poisoning. It's a little too convenient. But viewers willing to entertain such a scenario will enjoy the episode.
Data's adventure in the village is interesting enough. Ronnie Clark Edwards of Waltons fame is strong as Talur, a woman who leads her village academically in a society just beginning scientific progress. After villagers start getting sick from radiation poisoning, we get exactly the reaction we expect: a round of the Salem witch trials. But there's no legal proceeding, a desperate village impales Data right as he delivers the cure into the town well.
The subplot with Troi earning her rank of commander deserved more time. The premise of the final test of a commander seems realistic. You have to be willing to order someone to their death to save the entire ship. It might have been fun to let the viewer "play along" with the disaster-handling task, and even give us a hint at what she needs to realize. Instead we watch her take the test once and Troi immediately figures it out the second Riker wants to fail her. One wonders: just how many commanders are we going to have on this ship until someone gets transferred?
An interesting note about this episode is you don't even see Picard until the final scene when Data recovers in sickbay.
This episode isn't in my favorites, but I don't mind seeing it from time to time either.