I have a Garmin Legend and my son has a Magellan. Some features I like about his and some I like about mine. Overall, I'd keep mine but that may be just because it is the one I am accustomed to. But one thing I have noticed, the Magellan seems to update more slowly than the Garmin. We can go out together and as we are walking to a target location, my garmin will show us getting very close while his shows we still have a little ways to go. I'll stop and he'll keep walking. By the time his shows he has reached the target, he will be perhaps a hundred feet past it. Then in another minute or so it will "catch up" showing he is past the target and he will be coming back. When getting close he really needs to walk slow to not out run the Magellan's updating.
I have noticed the same thing with my Magellan Gold and the Sportrak Pro. You will over shoot the cache if you walk very fast. Especially in tree cover. Magellan is all I have ever used, so I don't know how to compare with Garmin. I am seriously looking at the new Garmin 60csx. They are quite expensive so I'm still saving for that and reading the forums about them. Some like it, some don't.
I like my Garmin 60c but I also have a Sporttac yellow and HATE it. Ozark Mtn Ghost bought the 60csx and can not tell the differance in the 60c and the 60csx.
I'm a diehard Magellan user. I went with Magellan because in the late 80's Magellan was one of the few GPS companys out there. I can remember the Magellan, Ashtech, and Trimble ads in the surveyor publications. I think Garmin was making fish finders back then.
Anyway, both companys are now the leaders in the hand held world so it's become like Chevy vs Ford.
Speaking of the early days. I can remember when the surveyors setup GPS equipment in the middle of the night and collected data until the satellite reception window closed.