Even though this was the one that started the whole franchise, it's by far the worst thanks to its never ending sexism. There's no real development for any of the supporting characters, there's just Kirk looking for a new hookup and women who are there just as his love interest dressed provocatively. The show might as well be called _Kirk and the ladies_. If this show had been my first venture into Star Trek world, I would have given up watching 2-3 episodes in. Thankfully, I decided to follow the suggestion found online and started with TNG, DS9, VOY, etc. and left this one for the end. I managed to finish it just because I was already very much invested and in love with the franchise. There is however one good thing about this show and it's Spok. He's the most interesting, the smartest and kindest character, not to mention the only one we learn something about besides Kirk.
Either way, the show doesn't have a rewatch value for me at all.