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.

You should try the stargate series next if you haven’t. They supplanted Star Trek in my pantheon. There are also some time travel series more recently that are also quite enjoyable; Travelers and Continuum.