This is the only Mac GPS application that really works well with all types of scanned maps.

The support is excellent, I had problems with a GeoTIFF file that used unusual tags and the developer had supplied me with a new build that fixed the problem within a day.

The main gripe I have is that the UI is fairly clunky, it has obviously been updated from a Mac OS 9 codebase with few changes and needs an overhaul. The floating dialogs would be much better incorporated into the main map screen so that there is less window switching. The preferences also need to be consolidated into one place rather than being spread around the menu system. I'd also like to see "live" updating of the position of the mouse cursor a la OziExplorer on Windows.

However, if you want to use your GPS with topo maps on a Mac then this is the solution that you're looking for. I successfully uploaded and downloaded tracks, routes and waypoints and it worked very well.