When the show was in production and airing on a weekly basis, it was my favorite Star Trek series. In fact, Voyager was the first Star Trek series I watched from start to finish as it was broadcast. I was too young to start on The Next Generation and I didn't really "get" Deep Space Nine.
My tastes in Star Trek have changed a lot since Voyager ended back in 2001. For one, and I posted about this late last year, I sat down and watched all of Deep Space Nine from beginning to end - having not seen all of it. Once the dust settled, I decided this was my favorite of the contemporary shows. Voyager probably falls in fourth place for me; but that doesn't mean I view it as such.
I was watching the episode "Bliss" last night from the fifth season - a very underrated in my opinion, and I still enjoyed it quite a bit. In the later years when Voyager was producing some fairly subpar episodes, I still felt that it was watchable.
There were elements that I found frustrating; such as the almost complete lack of continuity (would this be right?). There never seemed to be any sort of continuation from previous weeks. The best way to sum this up, remember the second season episode, "Deadlock", where we discover Voyager was split in two - the "real" Voyager being the ship that was torn apart by the other's proton bursts. When the episode ends, we're left with the "real" and unbelievably damaged Voyager, but next week the ship looks like it's fresh out of spacedock.
I remember being shocked back in the fourth season episode "The Gift" that we still saw Voyager equipped with the Borg enhancements from "Scorpion", the previous week. And correct me if I'm wrong, because I always think I am, but wasn't sick bay blown up in "The Killing Game"? And then, there it is, as if nothing ever happened, in the next episode?
That was the big thing for me on Voyager - there were never any consequences to some of the events that took place.
One last thing is that I don't feel the show used its premise to the fullest. You actually see hints of where it could have gone in the early parts of the second episode. First off, you still have the conflict with the Maquis and Starfleet crews, but the other thing that I feel goes unnoticed is the scene in the briefing room. Captain Janeway and the staff are discussing the best ways to preserve their energy resources, but by the time this episode wraps up, all is well on both fronts and are never really a concern again.
I totally agree with what someone said earlier in this thread about how TV grew up, but Voyager did not. That is an excellent way to put it.