My lecturer once joked, "The practitioners in England carry Glanville Williams or Smith and Hogan to look smart in the courtroom. If you carry William Wilson, you'll look stupid."
This sums up the quality of the text. Wilson writes like a poet, making it hard to grasp the principles. He throws in bombastic words every now and then and writes in mega-long sentences. Nothing wrong with that if he's Fitzgerald, but textbooks should be as coherent and straightforward as possible. He's not running for the Pulitzer, after all.
However, if you're assigned this book by the University of London, I'd strongly suggest you to read this for one simple reason: William Wilson is the Chief Examiner for your Criminal law paper (at the time of writing). He adores his book so much that you'll see references to this text in the subject guide, articles and examiner reports. But if his concepts are difficult to comprehend, you should check out Criminal Law: Text, Cases, and Materials by Jonathan Herring before coming back to Wilson. For the ambitious, I highly recommend Smith & Hogan Criminal Law.
Was assigned this text as the core textbook for my law degree. It wasn’t an easy read and it made understanding difficult for self-studying students like myself. I had to refer to other textbooks to grasp the concepts better. I would recommend the textbook by Richard Card and Jill Molloy. It had helped me big time. Note: there are a few typos in the Wilson text and had I not referred to the other texts I would not have realised the typos