My copy of Stace's first edition is looking very dog-eared and worn from too many field trips, so the appearance of version 3 prompted a well-overdue upgrade. Still as useful as ever - descriptions focus on the essentials, and the expanded range of species covers most eventualities. As other reviewers have commented, you have to know how to use a technical botanical key, but these are relatively easy to use (apart from a maybe inevitable reliance on overlapping measurements - are the lemmas 4.2 - 6mm, or 4.4 - 8mm long???). The nomenclature and taxonomic changes in this edition also justify the upgrade. My main note of caution is the robustness of the soft plastic cover, which will eventually part company with the pages within if you carry it round in the field for too long. I assume a hardback edition would've been prohibitively expensive, so handle with care or keep it on your desk. The other thing to understand is this is an identification guide, no more and no less - descriptions are inevitably short in order to pack in the species, so you will need to read more widely to learn more about a particular plant.