b5 > tng > tos > voy > ent > ds9
A lot of it for me comes down to time travel, and how it's been getting worse as we go. In TOS there were a few time travel incidents but they were handled fairly well for the most part. The rest of TOS was enjoyable. In TNG there was hardly any time travel, and the rest of it was ok, even if they did spend more time than I'd like dealing with internal matters, rather than exploring strange new worlds. DS9 annoyed me. It seemed that it was trying to be like B5, but without much in the way of overarcing plot (which was what made B5 great). When they did finally kick the overarcing plot into existence, it was badly handled, and the wormhole aliens were woefully underused (they didn't exist in linear time - so how come things kept coming up that they hadn't forseen/prevented?).
Voyager was a very nice idea, with ok execution. It's been a while since I watched, but iirc at first they had the most powerful ship in the area, and they kept on getting attacked by these annoying little ships, and they never fought back properly. Add to that, they kept on discovering quicker ways to get home, and not using them for some reason or another. The end of the show was painfully stupid. A few years tech advantage is enough to let them kick the Borg's ass? Seriously? When the Borg have been in space for millenia, whereas humans have been in space for a few centuries?
I didn't watch all that much Enterprise. There was so much bad time travel in the first season, it put me off. I will at some point go back and watch the rest, if only because everyone reckons seasons 3 and 4 are the best - but in the meantime I can't rate it all that highly.
Babylon 5 was of course the best, although once they'd moved most of the plot from season 5 into season 4, they should have either called it a day or come up with some good new plot for season 5. As it was, season 5 dragged, and I tend to skip it when I re-watch.
