So what's the point of having Base Camp? It seems that Map Source does all the same things. The only thing I can think of would be the 3D map views. But it doesn't work on my computer despite all the "help" I have got talking to Garmin support and engineers.
Aside from 3D, BaseCamp uses a tagged data approach that allows waypoints, tracks, and other elements to be readily shared between folders, whereas with Mapsource maps, the data is more strictly partitioned. BaseCamp reads KMZ-formatted Custom Maps, which is a big reason for my using it.. On at least some GPS models--like the Dakota--BaseCamp provides direct access to the contents. You can add and subtract waypoints, routes and tracks just as with any map. Not so with Mapsource--you can download, content, but you can't edit it.
Of course, none of this is worth anything if the program doesn't work on your computer. Mapsource feels like professional commercial software. Basecamp has improved, but I still think it best to regard it as a work in progress.
Have loaded it 2X to work with and each time pulled it off. One particular reason is that it doesn't accept that I have a valid CN NA map that MapSource accepts (unlocked in MS)
Basecamp also lets you use any maps that are pre-installed on your GPS without loading them on your computer. With my Oregon 400t connected, it reads the pre-installed US Topo 100k maps and displays them on the computer. This is not possible with mapsource; you would have to purchase the maps on DVD separately and install them. It also reads the maps from my Nuvi 1350 and lets me use them on my computer.
But perhaps the main reason to use BaseCamp is that it's the only way to download BirdsEye aerial imagery.
But if you don't see a point to BaseCamp... don't use it. :)
Have loaded it 2X to work with and each time pulled it off. One particular reason is that it doesn't accept that I have a valid CN NA map that MapSource accepts (unlocked in MS)
That sounds like you are missing the GMA file for your CN NA map. I assume you are using an older MapSource version (<= 6.15.7)? If you update to MS > 6.15.7 your CN NA map would also be locked. You can get the GMA file for your map from my.garmin.com.