Space: 1999 vs. Star Trek
I recently started watching Space: 1999 (I'd never seen any episode of it before), and I've watched the first 8 episodes so far.
The first thing I noticed about it was that it seemed to have a surprisingly big budget for a TV show. I was also surprised that the two top-billed actors were American (Martin Landau and Barbara Bain).
I find the characters bland, whereas Star Trek had some of the most memorable and iconic characters in TV history.
The premise is hard to swallow. They were being laughably optimistic when they chose to set it only 24 years into the future. Star Trek is set 300 years into the future, which makes the depicted technology a lot more believable.
Also, the idea that a nuclear explosion on the moon could not only knock it out of Earth's orbit, but also accelerate it to a speed sufficient to reach other galaxies in a matter of months, isn't even in the realm of science-fiction; it's just pure foolishness. An explosion on the moon big enough to knock it out of Earth's orbit would inherently destroy the moon in the process, and on top of that, humans couldn't survive the level of acceleration that would be required to reach such a speed in such a short amount of time, not to mention that such a speed isn't even known to be possible. The nearest galaxy is ~2.5 million light years away, meaning that even if you could get the moon up to light speed (a prospect which is beyond laughable), it would take ~2.5 million years to get there.
Star Trek, on the other hand, had a "warp drive," which made traveling astronomical distances in a short time believable. Plus they don't even go to other galaxies.
Another problem with the premise is that they can't have people being killed and equipment being destroyed very often because of how they are cut off from outside resources. This results in episodes where there appears to be a lot of destruction but it all gets undone at the end, tantamount to an "it was all a dream" ending.