V (well the Mini-series and V: The Final Battle) were decent enough, sadly the same can not be said for the series which continued on from them.
AS for the best US Sci-Fi show upto 1985, Star Trek would seem the obvious choice as it has managed to stay around for over four decades. A fairer criteria might be to say was TOS the best Sci-Fi show of it's era ie. the 1960's. Rather than trying to compare things from decades apart.
As for British Sci-Fi shows from the same era upto 1985, there are plenty to choose from. But really only one has had the staying power. Whilst some have remained in the public mind others have faded away
Captain Scarlet and the Mysterons
The Invisible Man
The Tomorrow People
Sapphire and Steel
The Day of The Triffids
I could go