As redboots said - both are for the hardware - Garmin and both use the software 'Mapsource' made by Garmin.
Garmin have a number of GPS units - you will want a 'MAP' unit to see the maps on the GPS .. a base garmin GPS does not display maps ..
The T4A uses logs from people who have travelled there ... so is to be trusted .. But there is little of it in the north of Africa.
The wanderlust comes from other sources and they can be out by say 300 metres .. or spot on. Version 1.7 is due out soonish and that should hve topographical info at 100 metre intervals .. of some use ..
You are best off having both .. then you can pick and chose what best matches what you see. I think what you use will vary as your location changes.
For Moroco - use Island Oafs MorrcoTopo .. free GPS Vector Map Morocco
Regards Frank Warner
motorcycles BMW R80 G/S 1981, BMW K11LT 1993, BMW K75 G/S