To my mind, this is where the third season really begins. On the surface it doesn't have much more creative worth than its two predecessors. I would never argue that it's a classic per say, but it's just more fun to watch, and Next Generation simply became more fan to watch once it finally figured itself out, which is what the third season is all about.
Like an episode of the original series, our crew encounters a situation that isn't what it seems, a couple of odd individuals who don't much care for visitors, and yet the more our crew pushes them, the closer they get to the startling truth. It's a formula that works so well plenty of other episodes from across the franchise liberally borrow from it in the years to come.
"The Survivors" also features (if you don't particularly mind a spoiler) another original series staple, a god-like being with its own ideas of morality, which turns an good story into an interesting one. As is usual, Next Generation does an established franchise trope with more nuance.
If you click the "Star Trek A-to-Z" link above, you'll also see that I've got a tiny obsession with the character Kevin Uxbridge's wardrobe, with is another reason why the episode remains memorable for me despite not having any particular relevance to the series or its cast (which are usually the ways to my heart).
On the one hand, I'm trying to be subjective about "The Survivors" and on the other, I know this is a personal favorite. I'll give the theoretically uninitiated the benefit of the doubt and assume that you won't necessarily share the exact interests I have. It's still a good one to at least sample for existing and budding fans of the series.
franchise * series * essential * character
Memory Alpha summary.