The plot definitely isn't much to write home about. I think what people remember about the plot is mostly the visual of the Cybermen waking up. But I think a lot of the base-under-siege stories have similar structural problems (endless the-base-is-captured/freed cycles) and this one benefits from only being 4 episodes.

I also think it looks good for what it is. Obviously it is impossible to really see it from contemporary eyes, but I have a hunch it looked good by the standards of the time.

Over on Dreamwidth, londonkds feels that there is also anti-semitism present in the the presentation of Kaftan and Klieg - while they are coded as middle-eastern/arab rather than Jewish, the idea that they have the money and represent a faction of intellectuals trying to overthrow society seem quite telling. I don't know if it struck you the same way at all?