During my migration from the dark side, I had to overcome a few challenges to make all my gadgets and software work.
I was fascinated to find, that Garmin supports Mac OSX completely and they even have a brilliant blog – http://garmin.blogs.com/my_weblog/applemac/index.html.
For the Garmin savvy, you will be delighted to find the Windows equivalent of POI Loader and Web Updater. Even better, you will find BobCat, the OS X version of MapSource. I think the application is still in beta and therefore does not support the clipping and synchronization of map-portions. This is not really a great deal, since I have the whole map of Southern Africa on the SD-card.
Garmin Bobcat functions the same way as MapSource and the interface is in typical OS X fashion more polished. Was great to see that I could upgrade my Nuvi 710 to the latest version via the MBA.