I watched all episodes of the original Star Trek series over the last two years. It’s not amazing, but it has its moments. Some episodes are great, some are dumb, and some are boring. Episodes are almost entirely self-contained—no cross-episode story arcs.
I watched the “remastered” versions on Netflix. The quality is good, though I disliked basically every CG effect that was added. They look cheap and feel out of place from the rest of the show, which retains a 1960s look. The rotating colored lights at the tips of the warp nacelles are especially ridiculous.
I’ve now moved on to watching The Next Generation. Everything is better: the stories, the scripts, the sets, the lighting, the CG effects. The cast is bigger and characters are better developed. The cross-episode story arcs add a lot of depth (e.g. Wesley and The Traveler, The Borg, Data learning more about his origins and family).
It took me two years to watch all 79 episodes of the original series, so it’s gonna be a while before I finish watching/rewatching all 178 episodes of The Next Generation.