TOS:
The yardstick by which almost all other science fiction shows are measured. Thank you writers for stealing the show from Roddenberry and making the three personalities we all know and love (Kirk, Spock, and Bones) the main impetus of the series. With some great side characters like Scotty, naturally.
TNG:
Sucked for the first two seasons. Was closer to Rodenberry’s vision of an ensemble cast, which sucked. Eased away from that, became better. Picard still talked too damn much. Less diplomacy, more photon torpedos please. Q and his ilk were terrific recurring characters. Klingons and their lives and politics were intriguing. Finally, the Borg made for good old supervillians that were plain evil - kind of like Nazis, in space.
Deep Spam Can:
Good drama, good sci-fi, but Star Trek without a starship? Meh. Still watchable. Sisko was badass, the Ferengi were an interesting Randian viewpoint cast as an alien society, the Cardassian/Bajoran/Jem’Hadar conflicts were a decent exploration of warfare and genocide themes.
Voyaj-her:
Couldn’t take one season of this one. Too many goofy alien species, too much of a dumb premise, too much RESPECK MAH CULCHAS, the GRRL POWAR of an obvious token female captain, a holographic doctor, and a black Vulcan made it completely off the rails for me. Introduction of regular space T&A to boost ratings confirmed my assessment of the series.
Enterprise:
Meh. Not bad. Broke canon. Decent characters. Tried to re-capture some of the TOS magic, but nothing could ever do that. Once again, gratuitous T&A showed that the producers had no confidence in the series and no respect for the audience.
BTW, as an instant watch/don’t watch guide for TNG, anytime you see the Will Riker character WITHOUT a beard, turn the channel.