I hate calling these reviews sometimes, especially when they're primarily one paragraph summaries of my thoughts....
The book is a solid adventure story -- it fits in well with the Tom Baker/Sarah Jane period of the series. It isn't at all a continuity-heavy story, and one that fits in a fairly neat fashion.
It's been a couple of weeks since I've read it, and it's sitting better in retrospect than even when I read it. Quite a pleasant surprise.
This period of NAs was really a bit grim -- The Pit, Deceit, and Lucifer Rising all sit towards the bottom of my rankings. Lucifer Rising is probably the best of those three, but both Love and War and The Highest Science are even better examples of books from the same period, and Transit -- while perhaps a riskier venture -- is also better than all of these.
It's an interesting first draft, but really needed some more work. There are some scenes such as those with Sam at the beginning of the book; which distinctly fail to be realistic, and start the book (and Sam) off to a bad start. There's also a few moments of strange continuity -- I get the impression that Tegan had never met any Doctor before the fifth, much less see a regeneration take place.
Most of the Doctor's characterizations are ok, but the Eighth doesn't particularly have any distinct personality (which is different from both Vampire Science and The Dying Days, which better capture the personality of the character as seen in the movie).
It does reference s past Virgin New Adventure; in fact the book has some elements of being a sequel to Blood Harvest. It also -- by sending the Doctor back through his own time stream -- could have the possibility of changing his own past, which could have had a Zero-Hour (from DC comics) like effect, both leaving the *basics* of the old series intact, but allowing for the occasional and inevitable retcon. (The Seventh Doctor's sequence is terribly difficult to match with any particular period in the New Adventures, I'd be interested in a theory... it must be, I imagine, directly before Room With No Doors, while Chris is off doing whatever he does when the Doctor wants to be alone... :)