My first recollection of watching Trek (and Doctor Who) was on re-runs when my father would take me to my grandmother's house to visit. About every two or three weeks. She lived in Galion, OH, which is about halfway from Columbus to Cleveland, and near to Mansfield, which just big enough to have its own local channels. As a result, we could always get two (or sometimes even 3!) episodes of Trek/Who. The local PBS/independent/network station would show different reruns.
Anyway, this was probably mid to late 70s. Probably saw nearly all the TOS episodes that way, and was a near religious TNG viewer, though college did make me miss some.
Watched the first year or so of DS9 but then stopped. VOY held me for 3-4 years, but then I stopped. Gave ENT a shot but waned in late S2. Have watched all 3 in their entirety on streaming, and improved my opinion of each, especially DS9.
If I had to rank them, TOS & TNG are far and away my favorites, DS9 far and away 3rd, and VOY/ENT neck and neck for 4th. Probably VOY if you press me. The good ones were really good.
As for new Trek, I am not the biggest fan, though I still watch & subscribe. The JJ movies are my least favorite by a huge margin (TOS by a mile for 1st).
I think I prefer episodic to serial, though I cannot lie and say the idiotic episodic nature of VOY did not wear on my after a while (infinite shuttles!).
Perhaps it is the length of this seasons (22-26 eps vs 10-12). This almost mandates less character development, particularly for secondary characters. Perhaps it is the need to preserve mystery and reveals throughout the season, and the plot gymnastics that requires. I just don't get the emotional punch from the new shows that often, too rushed for me. Though there have been a couple delightful exceptions.
I will say, there are some things that do NOT bother me: swearing, visual continuity (floppy discs and laptops aren't futuristic), dark tones (loved NuBSG), SJW criticisms (Trek has always been about this, RWNJs just have their panties in a bunch since Obama won), "not real Trek" criricisms (these are BS and have been levied against every Trek iteration since TNG).
The main things for me, I think, are as follows:
1) Less episodes. It took me a while to warm to every new Trek series. To emotionally bond with the characters. Especually those beyond the main 2-3, and even that took some time. 7 episodes, or 20, and I am not there yet.
2) Does everything have to be constantly life/death galaxtic destruction, end of federation, end of earth level threats? Yeesh. Sign that the show/characters cannot generate interest/urgency on their own, has to be plot driven instead.
3) DISCO: I am in the minority, but I really did NOT like the second half of the second season. Going for cheap tears on Ariam's death that were not earned and the massive internal plot continuity stuff (wait, I thought she had juice for only 1 jump?) was just too much. The constant change in writers/showrunners took a toll.
4) Star Trek as action over thinking.
Not that I mind a good space battle, or a fight or two, but high tension, low explosion/ body counts are much better (Balance of Terror, TWOK, Amok Time, Arena, etc) than constant/superfluous action scenes (Picard driving dirt buggies, all of JJ Trek, a lot of Disco).
Sorry for the length. But that is my $0.02. Though in fairness, if you'd have asked me what I thought of TNG/DS9 after 8 (or 24) episodes, I would not have been terribly enthusiastic either. And I think as S1s go, DISCO & PIC are/were both pretty good. Better than TNG/DS9/ENT S1s for sure (TOS1 is the beat S1 by a mile).
Though it is pretty good because of a string of pretty good episodes, but few (if any) real classics. Again, the serialized nature almost prevents it. One cannot tell if an episode made sense or not, or if what character X did made sense or not, until you view the next episode. Or episodes. You cannot put a bow on any episode after you view it.