I have now had a magellan colour, magellan meridian and explorist 600....and recently purchased a garmin 60Csx unit and appropriate mapping software for Australia.
Trust me..although people say a personal choice etc...i have found the garmin unit much more robust, many more maps available, and tons more features in the standard software.......
I should have bought this unit in the first place.....
Your choice..most folks stick with a brand..i have used both..and i must say from my early Wow factor with the Garmin compared with top of the range Magellan unit...i would go garmin.
I am sure many mfolks would disagree, however i have an explorist 600 sitting next to me that now refuses to turn on....
cheers,
Derek