The only truly bad episode of DS9 for me, and I feel it is the WORST Star Trek episode ever made, is PROFIT AND LACE.
DS9, taken as one 175-episode story, is in my opinion like THE GODFATHER part 2. It's actually better than part one (ST:TOS), but everyone likes the original best for sentimental reasons. :-)
it is hard to compare the various star treks. but one thing can be said about the original - all the later shows have topics that were originally shown tos.
tos did a good job of taking a science fiction setting, and making an important statement about the human condition.
the interplay between kirk, spock, and mccoy was tremendous. while i enjoyed scotty and the rest of the supporting cast, i think most any decent actor could have done the job. but the main 3 would have been hard to replace.
in tng, data was the character that made that show. i think the relationship between him and picard and him and jordi were both very good, and extremely different. in that picard was his boss, and jordi his closest friend.
in voyager, the doctor and seven made that show. it was good before seven, but the development of those 2 characters was absolutely outstanding. the only ridiculous thing they did was in the last episode, where you learned that seven and chakotay got married.
that whole romance was dumb. the character of seven was custom made for the doctor, and it was a huge stretch that she would have fallen in love with chakotay.
so far in ds9, miles is superb in his character. i love it when he and bashir get together - they are so totally opposite that it is entertaining. odo is also sarcastic in his good way. i like kira, but she is a little over the top at times.
although i was disappointed with the startup of ds9, i knew it must eventually get much better. cuz it lasted 7 years and had to live up to a high level - the only thing that star trek fans would allow !!
i had seen various episodes here and there during its initial run, but it is completely new to me at this point.