If you have the previous edition and are wondering whether to upgrade, this eighth edition is not a radical overhaul, but does take the book a definite further step towards being comprehensive. There has been a general tidying, including some clarifications to the grammar, but the biggest change is the addition of the opening 25 lines of 'Beowulf' - now giving a pretty well rounded selection from the original for those who want to read most of it in translation. It has very full contextual annotation, so that it is also an excellent place to begin a complete reading of the poem. Despite the expansion the book is actually thinner in the new edition, thanks to finer paper - very thoughtful of the publisher!
There are now other learner's guides to Old English around that use different methods to get over the initial hump (e.g. Pollington, First Steps in Old English; Atherton, Complete Old English (Anglo-Saxon): A Teach Yourself Guide (Teach Yourself Language); or Baker, Introduction to Old English), but the value of this one is that it will remain highly useful long after this beginning stage. The arrangement is traditional, with grammar and reader in separate sections. This means that the grammar can be laid out clearly and accessibly for permanent reference use. The long section on syntax is masterly, and is a fundamental reference for even advanced scholars. It doesn't have to be tackled entire in the early stages, and over the years will provide much illumination in your reading.
If you are working without a teacher, there is a detailed study plan giving the best order in which to take the Grammar. The Grammar is written in a fairly informal style, with quite full explanations. There's also a glossary of linguistic terms, and a lot of handy summary charts. This is primarily a READER'S grammar, although historical linguistic points are introduced where they help clarify the grammar (with more newly added). There's also an abundance of supplementary material, including a guide to further reading which ends up being a characterful introduction to the whole field of Anglo-Saxon culture.
The Reader now has enough depth of coverage to be like a self-contained anthology, taking in many of the best and most representative texts. So the comprehensive glossary now also represents a complete basic working vocabulary - which you can slowly absorb out of the corner of your eye as you continually look up words when reading!
It is 'practically perfect' now, but for a dream ninth edition of the book (in hard covers!) I would make four changes, the first three in the Reader:-
(1) A moderate expansion, particularly of the prose (now a little thin compared to the verse), just to round out its completeness as a representative anthology. Some suggestions (or at least good texts to try when you've finished working through this book):- a few more passages from the Anglo-Saxon Chronicle (both early and, especially, eleventh-century); the poem 'Deor' to represent bardic ('scop') poetry; a homily; selections from the Old English Orosius; extracts from the Old English verse translations of Genesis; the poignant Codex Aureus inscription; and a few charters and wills to represent official literature (and dialect).
(2) For each text a super-concise bibliography, giving at most four to six references to the most valuable pieces of criticism and analysis.
(3) A rearrangement of the Exeter Book riddles so that the solutions are given on a different page (back of the book?), and only notes that help with literal comprehension are placed on the same page. Or at the very least I would add one or two riddles for which there is no solution (or none agreed), such as Exeter 37. The riddles are usually read at an early stage of study, but tackling them without knowing the solutions makes for a brain-expanding challenge in advanced reading skills!
(4) A little more use of typographical tricks in the Grammar to aid clarity and ease of learning (e.g. different sizes and boldness of fonts to highlight what needs to be memorized). This would also help in using it for quick reference.
P.S. The 'Guide' (through several editions) has been my amiable companion in Old English studies for twenty and more years now, so it is sad to read that one of the authors, Bruce Mitchell, died in 2010. This is the first edition to which he has not contributed.