I am a big Star Trek fan over all. I am a big fan of all the series even the newest Star Treks. I got into Star Trek for the long haul during the J.J. Abrams reboots. Yet, I watched The Original Series and The Next Generation and continued.
When I began to watch Deep Space Nine I found it to be a cut above the rest. It was not all about the traveling and exploration. There was some in Deep Space Nine but it gave us a darker look into how things could be out in the very edge of space.
I love the dark grittier undertones and it showed that despite the fact that earth had come a long way since 2063 (First Contact) there was still suffering, crime, pain in the galaxy. I also liked how it tackled human issues never before tackled in many Star Trek shows. It was by far the most progessive of all the Star Trek shows as some things were only hinted at in others during the time of Deep Space Nine.
Don't get me wrong I am a well rounded trek fan but Deep Space Nine has my heart. It is the show I can watch over and over. The characters are somewhat more complex and somewhat deeper in the writing. All the characters have complex backstories and each one has a darker side to them in a way.
This is also the first time we see a full armed conflict in the Star Trek series that is fully played out. You hear of the Klingon War, and Romulan Wars often in the series and the lore but this was the first time if I am remembering correctly the first major war in the Star Trek shows that played out from start to finish.
I also like how funny the show can be for without it; the show would be pretty dark. I really enjoy the characters and the show also had some of the best costumes and props. I love the Gray uniforms especially. I also like how many of this look would transfer into the Star Trek TNG movies. It is great that Deep Space Nine does have many overlapping stories with TNG and VOY and that it really doesn't take away from the others. Even other characters are seen on Deep Space Nine from TNG and VOY from time to time.
To be full honest I like how these three make up a trilogy of sorts. I call this the 24th century trilogy for Star Trek. Deep Space Nine was kind of like Star Wars the Empire Strikes back in a way. TNG was a take on the lighter side of things like in Star Wars and New Hope, then the second act being a darker take and then a bit of both in Return of the Jedi. I know kind of an odd thing to say here since I am mentioning Star Trek's rival. Yet, it is kind of true.
I also like how the dialog gets deeper with this series. There is more you have to pay attention to. This is also the series where I found Star Trek is much deeper than the cheesy campy type stuff they see at first glance. Sometimes the campy stuff is pretty dang serious in Trek. Deep Space Nine gave us a lot of deep dialog that you have to pay attention to in order to find the true complexity of the series.
The show was rather cutting edge for its time. It is also the first series you see a whole build up of armadas of ships. I love the other series and their exploration habits but there is something special about Deep Space Nine. It is stationary (pun intended) but in that it is a mold breaker.
In short it is one of my top ten Sci-fi shows and my personal favorite chapter in Star Trek's long history.