As a frequent user of a 276C on my MC I would like to inform you that you have the best gps that can be found for MC use. But, as Neil states above, it is not like the Nuvis.
The Nuvis are good for taking you from one point to another address, the best (fastest/shortest) way while the 276/278/376 can guide you along a preplanned route.
The best way to do this in my opinion is to plan the route with the PC placing waypoints at junctions that will be passed along the route. Set the waypoint 50-100 meters after the road crossing and use the gps autozoom that will gradually zoom in when you approach and give you a clear view where to go. That is essential when riding MC!
Once you have learned how to place waypoints in the PC with Mapsource (for this Mapsource is OK) you can control the zooming in/out perfectly, no other gps can do this as good as the 276! No other gps can show the small roads at high zoom out as this gps.
The bad thing is as said the memorycards but 512MB is what I can live with for a trip over a few days. And I have a Nuvi200 also on the bike for the few occations when I just want to ride to an address, normally it shows a topo map.
Typ-ing of the CN map with high contrast look (black roads, white background) will also give fantastic readabilty, also in bright sun.