I was pleased as punch about the first three—Vicki, Zoe and Liz Shaw! Well, those are only favourites of mine. Vicki's was fantastic, although I was very slightly unsettled by Maureen O'Brien's voice at first, because naturally, she aged a bit since 1964 and one can tell. XD But I got used to that very soon; her "voice acting" was fantastic, if you can call it that, and I died a bit at her First Doctor impersonations. She sure noticed Hartnell's very specific way of ending sentences with "hmmm?" :D It's funny, when watching the show I always saw characters as, well, characters, and didn't give the acting performances a thought, whereas when I'm hearing audios I'm always so much more aware of how good the actors are being, bringing it all to life with their voice alone. Mind you, BF has wonderful sound effects that add a lot to the atmosphere, but really, Maureen O'Brien did a fantastic job. They probably all do ;)
The writing and story were also excellent; beyond the actor's performance, a lot of the overall effect rests on the writing, I suppose, and it was just really gripping and powerful. Like the other BF story I'd heard before, I found the story very intense and unafraid to edge into a bit darker territory than the show itself does. Family show. The fire and ice themes, Vicki's terror of the phoenix egg, Lady Georgiana's possession—it all gave me chills. And I wonder if this is a pattern in the Companion Chronicles, the fact that the character first appears to be telling the story to an outsider, but everything turns out to be connected with quite the clever twist around the end. The Cinder was a very creepy and interesting presence, and I liked seeing its connection with Vicki. The narrative being post-TARDIS travels also shed some light on what Vicki's life turned out like afterwards, clearly addressing the fact that she would find it ever so difficult to adjust to life in such an ancient place as Troy, with people whose state of mind were thousands of years behind her own, and who would view her as some strange and foreign person and often act wary or hostile.
Character-wise, we had Jane Austen, who was just fantastic! ♥ (And the Doctor danced the gavotte with her!) Also a little bit of Steven/Vicki-ish fun, because Miss Austen assumed, and Vicki was both like "but no, he's like a big brother!" and "well, I'd never thought of it like that". That was entertaining. I rather think he had a bit of a crush on her at least, I think I remember his calling out for her in some wound-induced delirium in The Daleks' Master Plan after her departure? Steven was not so very prominent in the story, that aside, but then again, he often did the action-y bits and little more in the show, too, as far as I recall. Which is why I vastly prefer Ian and Jamie to Steven and Ben—deeper characterizations… But he was nice, for the little he did. ;)
Overall, BF is marvelous and yes ♥