I really found the book useful, but I wish it had a method to highlight "must see" things better. I was in Dublin for a very short trip and had difficulty combing through the book to figure out what I should prioritize for my limited time. In retrospect, I wish I had purchased the Ireland guide, rather than Dublin, so it would have been easier for me to pick out the key things to see. On second thought, I might not have had the great, detailed maps if I had done that, so maybe I went the right route!
I've had great experiences with Lonely Planet guides in general, though I also love Let's Go. They don't have as many out there, but I buy the Let's Go version if it's available - better info for people on a budget, and lots of great "off the beaten path" suggestions.