Lost in Space was very good the first season, then the quality fell off fast.
Voyage was the same. Very good movie, good 1st season then the quality dropped off.
LotG and TT I remember as being really good but I tried to re-watch them and they aren't very good.
I liked Buck and Galactica, very fun.
Never cared for Man from Atlantis or Logan's run.
The Invaders. Love it, kind of the anti-trek. Well produced.
Space 1999. First season good, second season garbage.
UFO. Very Very well done. I love it and still watch it as much as TOS.
The Starlost. Just a train wreck, but you can't look away! Utter crap.
Anyway thats my opinion.