As a UKCAT tutor, I must say that I was very impressed by this book. It is written by the founders of Get into Medical School in Oxford who are both qualified doctors with lots of experience both of teaching UKCAT and of writing books.
`UKCAT for Dummies' provides a lot of background information on the UKCAT and how it is used in the selection process. There is an entire chapter on `UKCAT strategies that work' followed by four chapters dissecting each of the subtests. Each of these four chapters contains in depth teaching and further, more specific tips and tricks for each subtest. At the back of the book there are two full-length practice tests, together with full answers and explanations. If you are able to do them under timed conditions, they should give you a very good feel for the real exam.
The authors have done a very good job in choosing interesting questions, in so far as this is possible! Overall, the questions are probably on the tougher side of what you will actually get, but that is no bad thing in terms of maximizing your score.
Another positive point is the layout, which -- in common with most books in the `For Dummies' series with its team of professional editors and designers -- is simply superb. Boxed asides and even a few cartoons that help to break the monotony of revision.
In addition to all this, the book includes quite a bit of broad advice on the application process: choosing a medical school, writing a good personal statement, working on your soft skills, and so on. This might not go far enough, but this, after all, is a book on UKCAT and not a more general book on getting into medical school (of which there are many good ones -- I would especially recommend the most recent edition of `The Essential Guide to Becoming a Doctor').
In conclusion, this is a very solid book that will prepare you very well for the UKCAT.
I wish you all the best of luck with it.