Correct me if I am wrong, but doesnt Magellan also use proprietary mapping

software? (Mapsend). I could be wrong on this, but I beleive both Magellan 
and Garmin have their own specific mapping software that must be used for 
mapping. I think both brands will accept some other mapping software, but 
only for uploading and transfering of waypoints, tracks, etc and not maps. 
If you want maps in your unit, you have to use their own mapping software 
(Mapsend or Mapsource).

Yes, Scott! You are correct.
In my opinion this is what locks most users into brand loyalty (it has for me, for now).
So I bought a nice GPSr, and then spent $2-3-400 on mapping software, that ONLY works for that brand of equipment. What brand of replacement will I buy when the GPSr breaks (when I drop it!), or it gets lost/stolen, or I decide to upgrade?

I thought so. That's correct.

There are a few other programs that will upload waypoints to the GPSrs (well most of them, but not the Cobra!) , but if you want a map uploaded you have to use the manufacturer's software.