Mo,
I find the map data to be of some use in remote areas here as it shows lakes, rivers, railways and major roads and highways etc. The road/highway numbers appear on the screen (making it very useful in major cities) as do river names. I think the map error problem stems from the lack of accurate digital data for this region. I used the unit in the U.S. and it was excellent over there by comparison. As there are specific CDs for Europe it should be OK there also.
To answer your question - No, it is probably not really worth if you don't mind just having a screen with waypoints only. I previously had a Garmin 45 which gave me just that so I bought the MapSource WorldMap for the III+ to at least give me some map data. Put it this way - Even though there may be inaccuracies, I would buy it again. What is the point of purchasing a unit with this capability and not using it, when there are much cheaper alternatives available? I hope this is of some help.
Cheers,
Feret.