The Moonbase features the return of the Cybermen, and following this story, they had firmly established themselves as 'second favourite monsters' with the fans (the Daleks being first of course!)
A story from the 'cross-over season' when Hartnell relinquished the role, sees Troughton firmly settled into his new role, unlike previous stories - i.e. Power of the Daleks and The Highlanders, this story establishes Troughton's character as was continued for the remainder of the actors' time with the show.
Whilst some have argued that the Moonbase is merely a re-write of the Tenth Planet several months earlier, I would urge listeners to ignore that, true the story is about a base under-seige (but most Doctor Who stories at that time used similar plots!) but the characters and the content of the story are different.
Presumably most fans will have seen the two surviving episodes, however, listening to the complete audio soundtrack, allows the storyline to develop comfortably across the four episodes whilst hiding disasterous holes that were apparent on the visual material i.e. The Cyberman hiding like a Scooby-Doo villian at the end of an episode!!
The cast themselves come across well on audio, Troughton, as ever, having settled into the role, is excellent and the supporting cast are reasonable. However, the only nag might be that the introduction of Fraser Hines as Jamie has limited the dialogue of Craze and Willkes, and some of the base personnel are hardly represented.
Obviously the return of the Cybermen is a welcome for fans, and this story, being their second outing, is still fresh and effective. Being written by their original creator, Peddler, the story is well thought out. Furthermore, the new Cybermen voices give them a greater sense of power, unlike the 'sing-song' voices of The Tenth Planet.
Overall, the story comes across well on audio, the background music is chilling and helps to give the story suspsense on the audio medium. The narration is good, although at times it is lacking in places, and the Cybervoices are difficult to distinguish at times. Not a bad place to start for Troughton adventures, and the price is fairly reasonable.