Hi, there.
I've recently discovered OpenStreetMaps and its
possibilities for Garmin devices through mkgmap. I've loaded
the maps in my own device and I'm pleased to say that they
work really good.
The only real problem is when you want to enter and address
in order to go there: the city is found as you touch, but the
street search does not work at all.
I don't know whether you're already working on this or not.
I'm a computer programmer, so I could give a hand in case
it would be needed.
-- Baltasar