What a great thread! It has been such a long time since I've seen TNG that I have only vague memories of the episodes in question, if at all. I'm re-watching DS9 thanks to the magic of Netflix and will eventually move into uncharted territory with it starting in Season 5. I've watched B5 several times, and it's currently the only one of the three I own on DVD. (Trek is just so expensive!)
However, of the three, DS9 and B5 both edge out TNG overall in my opinion. They have also stood the test of time much better. If anything, I'd say both DS9 and B5 were way ahead of their time politically. It's very interesting seeing an episode by episode head to head. Voyager never did anything for me at all, but I'll still enjoy seeing comparative reviews.