The Fearmonger: Seventh Doctor and Ace get mixed up in future fascist leader's plans to take over Britain. Jacqueline Pearce (aka Servalan in Blake's 7) is excellent as the fascist leader herself. There is some interesting business with Ace's perceptions of herself and of the Doctor, being shaped by the Fearmonger creature (which itself had certain resonances with the Timewyrm of the New Adventures). But there were some definite plot implausibilities, and Sophie Aldred's husband, Vince Henderson, playing the shock-jock radio presenter, really didn't seem to have much of a clue what was going on, using accent rather than acting to establish the character.
The Marian Conspiracy: Sixth Doctor and new companion Evelyn Smythe visit the court of Queen Mary I. A peculiar combination of character and cliché, which really suffered in my estimation because I listened to it so close to the broadcast of The Shakespeare Code. Evelyn Smythe, played by Maggie Stables, is a delight and I look forward with great interest to future audio plays featuring her. But the play itself: oh dear. The reign of Queen Mary is not a well-known part of British history, and you can either deal with it properly or just go for a period romp; I don't think The Marian Conspiracy does either. And time-travel clichés are piled atop one another.
The Genocide Machines: The Seventh Doctor and Ace visit a ginormous library and confront the Daleks. Excellent. I loved: the Daleks themselves; the concept of a library storing all knowledge in the galaxy (impossible though I know it to be); the duplicate Ace demonstrating the Sophie Aldred can act (something I have occasionally had cause to doubt); and especially the many many references to other Dalek series - jungle planet with unseen indigenous species (Daleks' Master Plan), Daleks modified by their own plan who turn against the leadership (Evil of the Daleks), the Doctor's references to the interests of the Time Lords and the Matrix (Deadly Assassin), and a slight nod forward to the Dalek absorbing all human knowledge in 2005's Dalek story. Was this the first time Nick Briggs did the Dalek voices? He's very good. My one quibble is that I found it difficult to tell apart Louise Falkner, playing Bev Tarrant (who I understand is a recurring Big Finish character) and Sophie Aldred as Ace. Probably my hearing.
In summary: I'm generally enjoying these, and thought that The Genocide Machine was very good indeed - the first really gripping one I have heard. Though I think I may switch to one of the spinoff series for a while for variety's sake.