I like it. There's some super cheesy material to be had there for sure, even more so given the dated nature of it, but there are some great stories to be had. It's not my favorite Trek series by any account, but to me the foundation upon which better things were built upon. The TOS movies were even better than the show, TNG, DS9 and VOY all effectively for the most part improved upon the setting and concept. One may like the other series better(or not, as is their privilege), but one has to acknowledge that without TOS, the rest wouldn't have come into being.