I think so, but I'm clearly biased. The wife & I just finished watching it on DVD a couple of years ago (her first time; my 3rd or 4th), and the story still held up.
The benefit it had, versus more recent shows, is the 5 year plan was pretty clearly defined before it began. I think, in a lot of other shows, they say they have a 5 year plan, but what they really have is a five year network commitment, five year actor contracts, and are making everything else up as they go along (e.g. Lost).
Of course, I'm saying this whilst readily admitting that I don't watch a huge amount of TV these days, so maybe it's perception rather than reality.