At the time, it had been a while since the Cybermen had made an appearance on Doctor Who. It's not the greatest story and plot line, and there were some definite character problems (mis-castings), but somehow, I still felt at the end of it that it had been one of the best overall serials from the Peter Davison era.
The “classic villian” Cybermen are certainly more believable than in previous series, the acting is also not too bad (in comparison), and the ending is long remebered among fans of the show.
If you're looking for a good episode from the old series, this is certainly worth a watch.