The countries I've lived in since 1986 never got past TOS. So six months ago or so I decided to put that right and watched large slices of TNG, DS9, VOY, and ENT in that order. I saw well over half the episodes of all of incarnations except DS9, which I abandoned in disgust after the Dominion War deus-ex-machina.
None of my judgements are therefore the result of memories clouded by time.
I found TNG very, very weak (and the theme music extremely irritating).
DS9 was boring with very poor plots and a dreadful lead actor who spoke like he was reading from a script given to him one word at a time.
VOY recovered from a truly terrible first two or three seasons but never quite overcame the bad acting of Chakotay, Paris, Neelix, Kim, and the characterization of the captain (not Kate Mulgrew’s fault).
Enterprise on the other hand boldly explored issues where no (or very few) Star Treks had gone before. I don't think I skipped a single episode.
If I had to do it all over again I'd just watch ENT and TOS and leave it there (except maybe watch Trials and Tribble-ations at the end).