I've got Magellan Mapsend Topo for the US.
It works pretty well. It definitely adds lots more info to the GPS's onboard DB. I find it pretty useful and accurate. Adding the maps to my Meridian Marine using a 128MB SD card and reader is easy and fast. The Meridian loads the maps quick too.

Probably not the info you were looking for though, figured I'd throw it out there anyway.
Just my .02 cents US.
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...all I ask is a tall ship and a star to steer her by.