Honestly I was really unimpressed with the Garmin maps. They are scans of the paper maps, and the paper maps are in some cases old. My area of Squamish sits right on a boundary of 2 maps, one is metric and one is imperial. The topo lines on the Garmin maps did not line up at all, lakes were listed that did not exist and road data was just plan wrong. :-(
Unfortunately there doesn't seem to be a good alternative yet. The backroad maps on seem CD at least get a little closer to reality.
Forestry and paved road data is available from http://www.geobase.ca/. However there are no names listed, no bridges, or gate info and you have to put together the maps yourself. These maps do seem to be very accurate however (I have not been far off road with them though).