The Wonacott's, it seems, have been around forever, writing statistics texts of pretty good quality. I benefitted from their regression text when I was first got into regression analysis, and it was only afterward that I read their text on introductory statistics (second edition). Fortunately for me, it was on the shelf in the Free Library of Philadelphia.
Wonnacott's introductory text is a good one, but I doubt that I could use it with the beginning statistics students I teach every semester. Though they are not lacking in intelligence, they seem, almost everyone, to struggle with anything mathematical. Furthermore, insofar as the material is theoretical rather than practical and concrete, they struggle even more.
When evaluating Wonnacott's text, I think it is useful to bear in mind that they themselves are most accustomed to dealing with students in mathematics and economics. As a result, they are justified in assuming that their students have both the capability and interest to handle more difficult material. For students taking statistics under duress, however, especially those who have little or no interest in applying statistics to the disciplines they are studying, Wonnacott's otherwise solid text is not the best choice.
So, while I've enjoyed reading Wonnacott's introductory text, I don't think I'm selling my students short when I say that this is not the book for them. Levin and Fox they can handle, largly because it de-emphasizes theoretical concepts in favor of practical applications.
If you're so inclined, however, this is a good text for self-instruction or review. If you're using it for self-instruction, don't rush and don't expect to read the book from start to finish without struggling a bit with some of the concepts. Wonnacott's introductory text is sufficiently sophisticated that it merits close study and discloses some of the irritatingly counter-intuitive ideas that undergird statistics.