I spent one week in March in Lisboa and used the LP mainly to navigate the sights. The LP is well written and the author seems to know the city well. The information given is sufficient and reliable. The city is divided into 7 neighbourhoods, which definitely makes sense. Each neighbourhood has its own map. These maps inside the book make more sense then the pull-out map, which covers only the downtown area. For some neighborhoods the guide book offers a walk to explore the main sighths. I did two and was happy with the result. The tourist information (Ask Me Lisboa) has a better map (for free). For those interested in going surfing in Guincho, the information on p.127 is a little scarce, and the first phone number given does not work. There is an hourly bus from Cascais to Guincho, by the way, where infrastructure is underdeveloped due to the fact that there is only a beach and some (expensive) restaurants. Surf equipment for rental might be available close to the beach, but stores were closed when I arrived there around noon.
The recommended day trips to Cascais and Sintra were both worth their money, and the Lisboa Card (15/26/32 euros for 1/2/3 days) gives you free trains and free or reduced entry to most sights. If you arrive at Lisbon airport, there are more buses than the guide book says. Check time tables in front of the airport, which is only 7km from the center anyway. All in all, the guide book is a reliable companion which fits into the pocket of your blue jeans nicely.