My less than 5-Star rating is not for the original text and poetry, but more as an indication of how much I recommend this book for the general reader and how I feel about the marketing.
This is becoming my general assessment of many books on zen and meditation: if you are a beginner, it's going to be frustrating and obscure. If you are experienced enough not to be too intimidated by it, it's not going to offer anything new to you except a few moments of historical and cultural insight.
The book is a historical record. Hongzhi's poetry has a well-deserved place of honor in the history of zen, and a lot of his terminology seeped into greater zen culture. It's interesting to see exactly where he sits and what his influence was. The book should be treasured, and the introduction, notes and translation all skillfully provide access to the modern, English-speaking reader.
But I cannot recommend reading this book as an instructive introduction or support for a modern zen practice. And the style is too obscure to be satisfying reading for most people. The book wasn't meant for us - Hongzhi was writing using a symbolic language very specific to his time and place. If you don't find it boring and confusing, you're not being honest with yourself - but neither is that a fault. As modern readers, we're not capable of connecting to texts that were not written in our cultural context. Rather, it's our responsibility to take fresh approaches. It's not disrespectful to a tradition or cultural artifact, if you put it to rest when it is spent and done. You can still learn from it, but you can't pretend it's alive when it's not.
What I would like us to avoid is the idea that puzzling over foreign cultural concepts is part of the organic learning curve of the material - it is not.
This book I imagine is only really of interest to zen nerds (a term I use lovingly) or advanced practitioners / teachers / scholars with furious curiosity for all the details. Otherwise, it's not of much use or appeal. Pass, if you're looking for books on zen practice itself.