I ordered Frommer's Montreal and Quebec City 2011 guide prior to going to Montreal for a 2 week vacation.
I read some of the entries, I did not read the complete book. The information I found useful was how to get to the city from the airport by public transportation. Otherwise we have not gotten much use out of the guide. Our medium size hotel Le Nouvel is very nice, but it is not listed, so we had to ask for help in finding it. We ate once at one of the recommended restaurants: Eggspectations, and although it was good, it was not in any way special.
I was very disappointed with the pull out laminated map. It is small and very general. We replaced it quickly with the free official tourist Map of Montreal which is much more detailed. I wish I could find a better transportation map, the one that has metro and buses. Public transportation in Montreal is very good and with a 7 day Opus pass amazingly affordable. ($22/7 day unlimited rides on Metro and buses, there is a one time $6 charge for the Opus card)The free official guide to Montreal is a much more helpful publication.
There is a major music festival going on right now "Francofollies" it goes on for 10 days with numerous daily free performances on more than 4 stages, it was not listed in the guide.
Overall, we are having a great time in Montreal, it is a beautiful city and very tourist friendly. And I see now that I did not need the expensive guide at all.