"Silver Nemesis" may not be the most famously bad "Doctor Who" story out there, but I've yet to find one with fewer real defenders. There's some half-hearted 'it's fun nonsense' folk out there, but they are so vastly outnumbered by people who HATE "Silver Nemesis" or just don't like it. I don't think even "The Twin Dilemma" has quite so few defenders. For me, there's one thing that keeps "Silver Nemesis" from being my least favorite story, or even my least favorite Cybermen story ("Attack of the Cybermen"): the first episode. It's far, far from greatness, but it's alright and fairly enjoyable, there's some half-decent dialogue, and we hadn't really gotten to the plot or Cybermen yet (and really, this excuse for a plot is beyond confusing and ludicrous, and is just a complete and utter mess).
For a good laugh look through the DisContinuity Guide page for this (if you're reading this and don't own the DisContinuity Guide, shame on you, go buy it right now) and look at the 'goofs' section. "Silver Nemesis" has so many blatantly obvious goofs that it's hard to believe this was written by an adult, let alone that they had a script editor going through the stories. Quite hilarious, but even sadder.
The incidental music's crap, the guest actors are crap, the Cybermen are wearing cricket gloves, the story is a mess, episode 3 is one of the worst single episodes in the history of Who (so is episode 2, but it's not quite as bad, because the action scenes are amusingly bad). Basically this is a poorly-executed Cybermen version of "Remembrance of the Daleks", only it has about as much respect for the Cybermen as "The Chase" has for Daleks, which is only really a serious problem because this is supposed to be not only a serious story but a celebration of "Doctor Who", while "The Chase" is meant to be an episodic comedy runaround (and in my humble and rather unpopular opinion succeeds tremendously in doing so).
I'm a huge fan of season 25 and season 26 (the latter is better largely because "Battlefield" is watchable in spite of its poor reputation), and "Silver Nemesis" is all the worse for coming sandwiched between "The Happiness Patrol" and "The Greatest Show in the Galaxy", two acquired tastes, but also two of the most imaginative, smartest allegorical tales in "Doctor Who". It's absolute tosh.
3/10