I like watching the Twilight Zone episodes because they occasionally contain material that is used in modern day TV shows and/or movies. This episode blew me away because it indeed contains the precursors to transporter, force field, and replication technology, as well as time manipulation. Although the sound effects certainly show their age, the basic concepts are seemingly ahead of their time.
The show was well written too, since it had me guessing what was going to happen next almost the entire time. At first, I thought the romantic scene was a bit too much, but once the true meaning of the romance became apparent later in the episode, it was certainly needed for the whole effect. Of course, most of Charles Beaumont's work was excellent this way.
I enjoyed seeing a young James Doohan (best known to Star Trek fans as Montgomery Scott aka "Scotty") play a small part in the episode, minus the famous Scottish accent. Amazing coincidence that he plays a role in this episode containing so many Star Trek type technologies.