It’s pretty bad. The negative points include 70′s era animation and sexism, and some weak stories. Also, basically any time it tried to be funny. Each episode is only 30 min (well, more like 22), which is also a negative, when compared with the pacing of TOS episodes. Contains a number of the weakest Trek elements in action, notably the first stuck-in-the-holodeck and transporters fixing everything but only for the end-of-episode reset. There is a time travel episode, too, but that one was pretty good. The positive points are the benefits of animation: the two new bridge officers are non-human (tailed furry, 3 limbed orange guy), every new alien race is not humanoid (birds, slugs, Satan (really)). The Klingons are still the non-head-bump variety, though. Some of the effects are better. The ship designs are more varied, and more of them.
Probably of interest only to a serious Star Trek fan. TAS is officially canon material, so despite a number of issues, like Federation ships easily crossing the galaxy and a lot of basic science issues, the hard-core nerd will need to see it. Or SpockxChapel shippers.
I hope the automatic doors picked up on M’Ress’ tail.