The first science fiction work I ever saw was Space:1999, and i was six. Italian Tv had co-produced the stuff so it was aired around 6pm, not a very appropriate slot to broadcast scenes of people burned alive by their commander's lasergun... I probably had nightmares about it, but missing a single episode was out of the question. I got to see some first season episodes some twenty years later and I appreciated the show even more. I don't recall much of the second season apart Maya and Tony, so let me concentrate on the first one.
The electronic soundtrack and the opening credits (a kind of "Pulp Fiction" style guitar alternated with an orchestral version of the same theme) were very original, as it was the look of the Eagles: they are solid transport spacecrafts but at the same time one can see their pilots from the outside, so that Eagles seem vulnerable... well, they are, most of the time. Base Alpha is a large, well lit and comfortable place (some stylish seventies furniture, too) which is home and prison at the same time.
Anyway the most peculiar aspect is the atmosphere in Moonbase Alpha: The crew is shocked for what happened to them, unprepared to deal with the future, they don't agree with each other, they make mistakes, they often prefer not to show much emotion. No "Space as the last frontier" rhetoric, here. Space is cold and mistakes are lethal. That increases the realism even if 1999 is well past. Action progresses like a slowly unfolding bad dream.
Don't believe people complaining about bad acting. They just expect things that Space:1999 wasn't going to offer. The actors performed well. For example, Commander Koenig (the symbolism in the name is evident) is waiting for the "black sun" to swallow the base, he's talking with Prof. Bergman. He's about to break into tears but manages to restrain himself so that his eyes show only a little trace of what he's feeling underneath: A very good performance from Martin Landau, nearly impossible to find in better rated SF series/movies.
