My technique uses Garmin's new(er) .gmap format which IMO is a big improvement over the older registry based maps. .gmap is file/directory based and therefore compatible with both MacOS and Windows. Actually, you don't even need an "installer" for .gmap - just copy the .gmap folder to the ~\Garmin\Maps folder and it's "installed".

That's really all the installer is doing, aside from providing a little info to the user.
You must install the maps in this directory (which varies on different versions of Windows - see that other long thread) or Basecamp and Mapsource won't "see" them. If a user wants them in another location, that can be accomplished after installation using gmtk:
http://www.javawa.nl/gmtk_en.htmlThe same author also has a tool for converting .gmap back to the registry format (MapReverseConverter) if a user needs to (for using them with nRoute, for example).
Actually, I think the inno installer does write something to the registry, so that you can uninstall the map. This registry stuff is like a black art for me, since I come from a unix/Mac background.

But we've see lots of threads here relating to registry problems. Microsoft changed something in Win 7/64 which broke the old GPSFileDepot installer (IIRC,it used different keys for something).
Then there's the problem where people just delete the map files without uninstalling. This will break Mapsource - I think it will refuse to start with a cryptic message if you do this. And allowing the user to choose an install directory is just asking for trouble in most cases. This makes people think they need to "open" the .img files in that directory. We get lots of threads about this here. A very small number of users want to install maps in a custom location (not on the C drive), but they can do this with GMTK.
None of this is a problem with .gmap. Just throw away the folder and the map will be deleted, for example. I see all of this as an advantage - not to mention the universal format that only requires one download for both platforms. But Oz's installer is still available if you prefer it.
I would love to see others pick up the ball and improve on the basic inno script, but there hasn't been a whole lot of interest so far.
