I've had my trusty Garmin eTrex Legend for nearly 6 years now but its really only in the last year that I have seen its true benefits in terms of displaying maps and the benefits to me of having maps on it. I did have some official Garmin maps on the unit for a while but each time I travelled to a new location it was too expensive to get coverage, so for a lot of the time it was displaying only traces over the useless Garmin basmap. With Steve Ratcliff's mkgmap I can create maps easily for anywhere in the world based on the OSM data. I find that even though coverage in many places is patchy its still worth having, partly because it shows what is not mapped yet (so that you can divert to new routes to pick them up) but also because in reality I can still get from A to B, just that the route might not be the one I would take if I had a more complete version of the map.
Downloading the current OSM map data for the wider West Midlands I find I'm now downloading a 200+MB file from Osmxapi which takes quite some time (hours), perhaps I'll need to consider using the planet file soon. For now, the end result is a 6MB image file for the Garmin which is close to the limit for the 8MB of storage that the old Legend has available for maps. Upload to the Legend is also very slow over the Serial connection, which means that the total process from starting the OSM data download to heading out with current mapping is up to 4 hours. A bit long really. I can improve the process by upgrading to the latest eTrex Legend Hcx, which I guess I'm going to have to do sooner rather than later.