Bobcat is essentially a work in progress from Garmin - a rewrite of their Mapsource tool for the PC - to work on a Mac running OS X (as opposed to running Windows/Mapsource on the Mac using Bootcamp or similar).
It was still a Beta version last I checked with some features missing or not fully developed - or broken. Again, its a Beta and you are the QA tester. (it wants to keep sending reports back to Garmin on what is broken when you encounter issues running the software - they actually do fix things but it takes a while before they issue updates for "retesting".)
However, Bobcat does allow one to transfer tracks, routes and waypoints to and from the Mac and GPS unit. It displays tracks and such on the default WorldMap that basically is the same default map as on the GPS unit. For the most part, its worthless for navigating in this mode on the GPS, and its worthless for creating routes and waypoints on the Mac to upload to the GPS unit.
BTW - the 276C is one of the better GPS units for a motorcycle - a large color screen that's easy to read, can handle large amounts of waypoints and POI data. So don't worry about what everyone else thinks about what GPS you should be using.
However, with MapManager and MapInstall, you can move maps from your Mac to the GPS unit. Unfortunately, you also have to use MapConverter for converting the PC based maps to the Mac format. I say unfortunately, in that MapConverter runs only on a PC - so you have to have access to a PC to run the conversion software, then transfer the converted maps over to the Mac.
Try doing this when you are on the road, outside the U.S., sitting in your hotel room, when all you have is a Mac. Stupid method if you ask me.
But it works, which is a step forward for Garmin in recognizing the Mac as a viable platform.
If Garmin gets its act together on this software set, then the Mac is indeed a worthy computer for use with their GPS units. It'll do what you need it to do for the time being (unless of course, you want to install maps and that could be an issue - I had major troubles converting Tracks4Africa maps).
Chiang Mai, Thailand