I am used to travel without GPS, but now I got one and I loaded different maps to check out their detail. I am interested in Africa and I am looking for dirt roads or small paved roads. So, that's what I want from my maps and that's what I compared here.
Here is a comparison about Mauritania:
Open Street Maps
Lonely Planet guide
International Travel Maps
Another comparison about The Gambia:
Open Street Maps
Lonely Planet
International Travel Maps
OSM maps are the most detailed digital maps I found. Still, it's clear that they don't have enough details on Africa. I mean, even Lonely Planet guides, which are not proper maps, are more detailed! So, a good printed map like those from ITMB is invaluable, I think, if you really need some detail.
Except for Olaf's Morocco map, I didn't find any other digital map which is detailed enough to replace my printed maps. I know it's a pain to carry printed maps for some 40 countries, but I think it's very rewarding if you are looking for a lot of off-roading. I am planning to carry about 10 maps at a time and get the rest when I get a parcel from home.
That's not to blame OSM maps. OSM maps are made by people like us, anyway. Sure I want to contribute with my traces and make OSM maps even better.
If you know any other digital map which is more detailed on Africa, please, suggest it.
Cheers!