As episodes go, this is another one that's gotten creaky in comparison to later, better, takes on the destroyer vs. submarine-style starship duel. I did get a chuckle out of the 'silent running' on both ships, complete with whispers.
Mark Lenard (Sarek!) does an excellent job as the Romulan Commander, and Lawrence Montaigne is this weeks insubordinate officer. Those guys were a dime a dozen back then! Also, widows.