Every TOS fan compiles their own ordered list of episodes; each, I imagine, headed by a dozen or so "must see" titles that epitomize classic Trek. These lists may sort "Primo Trek" in more or less different orders but most inevitably do appear near the top - they're just that good and one never grows tired of watching them, unedited whenever possible! (Many prefer "City" but it's hard not to give "Seed" sufficient credit for breathing new life into the enterprise.)

Then come about twice as many "very fine" episodes that can in no way be called inferior except in deference to the superb panoply coming before. At the bottom are another dozen "turkeys," so nominated only relative to the rest of the original series since they might otherwise pass for better episodes in the oeuvre of the later series. Who knows, maybe "T'Pol's Brain" - or choose other organ(s) - will highlight ENT's next season!