This was actually the first time I have watched this story, having missed it as a kid and only recently bought it for my collection, so I come to it with a relatively fresh perspective.
I have been watching my Tom Baker collection one by one in sequence from the beginning, ROBOT (Story 75), with an eye towards seeking out the best of early Dr. Who... and THE ROBOTS OF DEATH is definitely not one. In fact, in brutal honesty, this is the first "mediocre" adventure out of the 16 serials so far for two very particular reasons:
● Those hats! Jeeze, as much as the art deco settings are wonderful to look at, those crazy hats upstage EVERYTHING. It's like passing by a bad accident, you struggle to keep your eyes away from focusing on it. It's an actual relief towards the end when the remaining crew is running around without them on. Even the players made obliquely unhappy references to them in the documentaries and commentaries (there are two separate commentary tracks on this edition).
● The Mine Crawler captain, Russell Hunter, and the baddie, David Collings, give very creditable performances. However, the rest of the crew act in the most theatrically melodramatic way that it makes even me cringe. It -really- is over the top, and nothing in the preceding 15 serials can compare, not even the wooden performance by the Court Astrologer in THE MASQUE OF MANDRAGORA. One of the truly sparkling aspects of all the adventures, in spite of a beggarly BBC budget, is the awe inspiring, highly accomplished actors and actresses that jumped for even a small role in Dr. Who- yet in this particular case, I think Television Presence was subsumed in Stage Exaggeration.
All the other elements are good (well, maybe not those robot shoes): plot, pacing, settings, subtle details galore. Certainly get THE ROBOTS OF DEATH for a collection, but if simply seeking the best of early Dr. Who, skip this and head directly to the next serial, the seminal THE TALONS OF WENG-CHIANG.