I watched all of TNG, Voyager and DS9. To me DS9 will always be behind the other ST series.
I felt like it was a bit too much of the social stuff, maybe because it plays mostly on a station instead of an exploration vessel, but I guess that is exactly what people like about it. The characters and their development and so on. I liked the Garak character for example, but disliked Zisko being some chosen one for the wormhole gods or something. I much prefer Data, or Picard or most of their crew, even if they don't develop as much.
Well, to each their own, they are all good series to watch.
>it was a bit too much of the social stuff
Because clearly none of the other series focused on social stuff, except...
TOS, which featured an interracial cast (and kiss) in the 1960s, where nearly every episode was thinly-veiled commentary on communism, where they visited a literal Nazi planet, where they had a black woman as a bridge officer (in the 1960s)...
TNG, which went into deep moral arcs, looked into military tribunals, witch hunts, had entire movies about mindless bloodlust and environmentalism/colonianism, and so much more...
VOY which.....honestly, if you don't get the point by now I'm not going to spend more time listing examples.
Star Trek was BORN "woke" and has always been there, and anyone who claims otherwise was never really paying attention. Star Trek EXISTS because Gene Roddenberry put social commentary into his show "The Lieutenant" which was too controversial for the actual US Military so he had to make a new show set in the future to make all the same points but with less oversight from crusty generals.
We recently watched all the 80's and 90's Star Trek for the first time. So it's really interesting to compare the series' from the modern perspective.
TNG is a classic, with the classic crew and after the first hiccups is some of the best scifi of all time. Absolutely great actors and amazing writing.
DS9 is the weird one. I do really enjoy the trajectory of many of its characters: Sisko, Odo, Bashir, Dax (one of my favorite characters in all ST), O'Brien, Quark, Kira, Worf, Dukat, Garak, Damar... The list of great characters in DS9 is the best part of this series. The last season was a definite letdown for me though, and I didn't like the ending at all.
Voyager was the surprising one. I expected a lesser series after reading the old discussion about the three Treks of the 90's. But wow. It's banger episodes right from the start, one of the most badass captains in all of Trek and in the fourth season arrives my favorite scifi character: Seven of Nine. There's a lot of great episodes here, and some filler. I didn't like how some characters never went anywhere. But there is more good here than mediocre. As a series I like it more than DS9, I just wished the other characters were up to the writing of Janeway, Seven and Doctor.