For me:

TNG - Nothing to say about it, if you haven't seen it, then it probably isn't your thing. If you have seen it, then you know all about it.

DS9 - It does get pretty good. I haven't even seen all of it yet, but I really enjoy it.

VOY - So much crap in that series, but hidden among it all is some really good stuff. Being lost in an unknown part of space allowed the show to explore "strange new worlds" and tell some pretty interesting and bizarre sci-fi stories. I missed the last few seasons of the show, but I did download and watch the finale at one point.

And Picard will always be my favorite. I like the intellectual captain angle, the classic literature, and the earl grey tea.