Plot: A series of mindless murders on 30th Century Earth leads the Doctor and Benny to investigate. It's not bad, spanning interesting planets but relies heavily upon continuity and knowledge of the established future history of Earth.
Characterisation: The Doctor (7) is extremely well written, and (for the most part) it sounds as if Sylvester McCoy is speaking straight from the page. Having not read much of Cwej & Forrester, they seem encouraging and likeable enough (Cwej especially). Benny is perhaps the most consistently drawn character of the entire series and here is no different. It's disappointing that Vaughn comes across as a psychopath, rather than as the calculating adversary of his Troughton-era appearance.
Continuity-fest. Yup. It starts off with the standard Virgin dystopian future, this time set in the last remnants of Earth Empire (c.f. The Mutants). Given the presence of Tobias Vaughn, there are myriad references to Cybermen; it's a shame that he was brought back as a villain. Also, it gets sickening how much good, old-school Whoniverse villainry Vaughn pins himself for.
Other: Can't work out for the hell of me what the book has to do with any Original Sins. The Hith are less convincing than any alien race since the (also sluglike) Gastropods. Vaughn's consciousness moving between every INITEC 'bot - but only being in one at any time - is perhaps the most impractical, least-useful (when to be in which bot?), rubbishy bit of AI in the Whoniverse, yet still serves as a key plot point.
In a word: Introductory.
For a full review, visit Original Sin's review at Books with Balls.