After the controversial, but hugely imaginative, Transit, The Highest Science is a low point for the NAs' attempt to tell stories too big for the TV. I've liked a lot of Gareth Roberts' stuff down the years and the era with which he's most comfortable, the team-up of the fourth Doctor, Romana II and K9 gave us two of his best books: The Romance of Crime and The English Way of Death.
The Highest Science hankers after that era but fails to make it work with the increasingly dark angsty tone that would characterise the NAs. The storyline is inconsistent - attempts at Douglas Adams-style digressions fall flat - Bernice taking a drugged out ride with a bunch of losers purely to get her to the right place to reconnect her with the Doctor is utterly contrived and seems to be there purely to eke out the word count and the Chelonians are neither funny or menacing, perhaps because the author tries to make them both.
Characters get killed off randomly almost because the author seems to decide he's bored and feels like throwing a murder into the mix. And the book really just stops at a certain point, rather than has an ending. Paul Cornell eventually resolves the ending 39 books later.
All in all, a very weak novel and thankfully not a direction in which the books continued. Some NA authors peaked with their first novels: IMHO, Paul Cornell's best book was Timewyrm: Revelation, Mark Gatiss's was Nightshade and Kate Orman's were The Left-handed Hummingbird and Set Piece. Other authors like Lawrence Miles and Gareth Roberts started low but became much, much better, eventually writing some of my favourite Who novels.
The Highest Science is part of the loosely-connected 'Future History Cycle' which began with Love and War and ended with Lucifer Rising. This sequence of novels was pivotal in developing the continuing style of the NAs and as such is a mishmash of styles and ideas, with many people loving some of the books and hating others. After Lucifer Rising, the series settled down and we lucky readers had years of great novels to work through. Of this cycle, the likeable Love and War is required reading for the introduction of warrior Ace and Bernice Summerfield, as are Deceit and the excellent Lucifer Rising. I loved Transit and The Pit is . . . well . . . a weird but often fascinating tale giving more background to Time Lord history, although it literally sells Bernice up the river to keep her out of the way (a change in schedule meant that the writers of Transit up to Deceit were all writing without a complete character outline for Benny and had to sideline her.)
Anyway, The Highest Science is readable enough fluff, but there were much better books before it and many more to come!