I have been all over the place in Canada in the last few years. In general Garmin maps have been very good. In growing areas the new bits are not that great but I suspect that is more of an issue with the local goverment updating the cartography.
Garmin City Navigator has been good on road and the maps in my Zumo 660 - they may just be newer version of CN - have worked well off the beaten path. I also have a few backroad map cards - I do not think they will auto-route but the detail is amazing. The Garmin basemap is not that bad if you stick to the main highways but I know few motorcycle riders that like to stick to "interstates"