I also recently decide to watching DS9 a few months ago. I'm at the start of Season 7 right now.
Some random thoughts.
1. A lot of talk about "Paradise." This episode is prob the starting point of when DS9 starts to "get good," in general (a few gems in S1 aside)
2. Compared to TNG, there's a lack of techno-babble / techno-solutions to a lot of problems with DS9. Talk is relatively simple, as are solutions. For those expecting some inverse/modulated tachyon/neutrino/graviton pulse/beam to solve every danger, those people will be let down.
3. They really overdo 'time travel.' There's at least 10 episodes throughout the 7 seasons where someone, somewhere, goes back in time. After the 3rd such episode, this theme gets extremely lame.
4. Someone apparently sends the producers a memo that the show has a stale non-human element to it during season 5 or so, and all of sudden there's like 3+ love relationships going on.
5. The stars of the show are Du'cat and Garak. Any episode with them tends to be above average.
6. Not really sure what to make of Morn. It's as if this character is part of a running joke. They never show him doing anything, but everyone tells a story about him. He's such a pure violation of 'SHOW your audience, don't TELL your audience' that I can only really understand him as a joke. But it's not that funny. He finally gets an episode about him in Season 6, but whatever happens in the episode does not really justify the 5 season buildup to it.
7. There's considerable filler in DS9. Usually after a major set of events, you'll have like 5-7 episodes of character development, with each episode focused on one character. The thing is it's usually not how they have recently changed, but more back story as to flesh them out further. The former would have been more interesting.