I was a confirmed Niner from the moment Emissary first aired. I grew up watching reruns of TOS after school and watched all of TNG in first run on TV...but DS9 to me was something special. Different, and special. I knew it was going to be a darker show - a less 'squeaky clean Federation' show, right from the start, and I liked that.
That said, I really liked TNG a lot when it first aired. Much more than I do now. As I said, I watched every episode and really loved it at the time...but I think a few things conspired to put me off of TNG slightly, to where I now consider it 'okay...but nothing special'. And those things are:
1. TNG has aged very poorly - especially the first two seasons, but really, the whole show. And I am not talking here about just special effects and costume styles, although those are certainly at issue. I'm talking here about the 80's PC mindset that permeated the show - a mindset that was not prevalent in TOS...and was not prevalent in DS9 either. That whole "We have evolved and as the superior society, we are now out to teach the universe our ways" is just nauseating to watch now. So I have to pick the TNG episodes I watch very carefully, so that I watch ones that are devoid, or nearly devoid, of that nonsense. When I do that, I enjoy the show much more.
2. The movies - specifically, Nemesis, but to an extent, Insurrection too. Nemesis was one of the worst movies I have ever seen - bar NONE. If it hadn't been Star Trek and therefore an ending I probably needed to see, at the very least to post here at TrekBBS, I'd have walked out of the theatre, it was so terrible. I can't even believe that movie MADE it to the big screen, it was so bad. Giant plot holes that you could steer a starship through were, incredibly, completely overlooked. I mean, we are talking major issues like...say...the motivations of the central characters! WTF?!!! And because it was perhaps the worst-written movie I have ever seen, it was, frankly, an insult. Because the message I got from B&B was "Yes...those dopey ST fans will watch ANYTHING with 'Star Trek' in the name - we don't even have to TRY to make a good movie", just slap "Star Trek" on a pile of steaming shit, and we can watch the Benjamins stack up. Screw those dumb nerds! We can throw them any old bone, and laugh at them all the way to the bank!" That, to me, is what Nemesis screamed. And it didn't help that I was sick and tired of Data's ongoing drama, LONG before they killed him off, to the point I was GLAD when he finally died.
As for Insurrection, I'm mainly just mad at the slight to DS9, like it didn't even exist....and the fact that the flagship crew of the Federation was off on this silly little mission when the entire AQ was about to fall to the Dominion....a conflict which barely registered a blip on the radar of this film.
3. Marina Sirtus. Jesus, is this woman annoying! And Frakes isn't far behind. First, she makes those nasty remarks about DS9 in the press (this coming from an actress who, by all accounts was the weakest link in the TNG cast!)...and then her and Frakes, in coordination with B&B, co-opt the Enterprise finale and turn it into a TNG episode. Not that ENT was all that great of a show...but they DID deserve their own finale, fer cryin' out loud - especially given the fact that the actors on ENT were great - it was the writing that normally was the problem on that show. What B&B, Frakes and Sirtus did to that cast was abominable and completely undeserved (especially given that the fault for ENT's failure rests squarely WITH B&B - the same guys who punished the ENT cast for their own lousy mistakes!). And yes - while I do chiefly blame B&B for the ENT fiasco, Frakes & Sirtus were certainly greedy enough and arrogant enough to participate without reservation in this massive insult to the ENT cast. Sirtus is by far my LEAST favorite Trek actor - she's a terrible actress who can barely get a job outside of Trek...but who still, incredibly, has the arrogance to diss DS9 en masse...and steal the ENT cast blind. I can barely stand to look at her. Seriously.
Anyway, the bottom line for me is that TNG sat alot better with me when it was on than it does now. I love DS9 & TOS and I quite like VOY most of the time. But TNG - I really love certain episodes...but the items above have sort of ruined a lot of the show for me...so on average, I rate it as 'okay'.