I don't think you're going to go wrong with either a Garmin or a Magellan. Between the two companies they represent about the best value/price ratio. And I won't even say that one is more expensive than the other. In both companies, the marketing people have done their homework. Comparable models are usually priced identically. Maybe one is $XXX.95 vs. $XXX.99 for the other!
That being said, like Coltdriver, I prefer the Garmins because the one advantage they do have over Magellan is that Garmin stores all of their programing in flash memory vs. being permanantly burned in with the Magellans. Garmin then offers free downloadable upgrades on their website. That way you always have the "newest" version of any particular product. IT's only a software upgrade BTW. It doesn't let you do anything like upgrade a III to a III+ (even if they do look like the same unit.) In my case I have a Garmin StreetPilot that I use in my cars, a Garmin 295 in my plane, along with my original Garmin 45 (Which was before they used flash memory) for hunting and geocaching. The StreetPilot has been upgraded about three times since I bought it. The most significant upgrade was to add a (then totally new) feature that allowed you to list upcoming exits when you are traveling a route and look at the services available at each one. The original software allowed you to look at the "nearest" services however not organized by direction and not listed by exit. Over all, a pretty cool upgrade for free!
BTW, both the Garmins and Magellans allow you to load maps to flash memory in their mapping units, so again, no particular advantage there. What I refered to in the previous paragraph is that the Garmin operating system can be upgraded.
As far as which models get better reception, it again comes down to a question more of models than manufacturers. Both companies make models with active (think powered) and passive antennas. In good signal conditions it doesn't make any difference which you have. With poor signal reception the active antenna has an advantage. Antenna placement "clear view" is much more important than whether the antenna is active/passive. BTW, some units use either type antenna and unit price doesn't seem to play a major part. My Garmin 45, the least expensive unit I own, has an active antenna. The StreetPilot and 295 both use a passive antenna on the unit however the remote antenna is active! One of the electronic engineers here at work (who's very happy with his Magellan) says that the only reason that the remote is active is that the wire to it tends to act as an antenna itself and pick up electronic noise. The active antenna keeps the GPS signal above the noise and keeps you from losing weak signals. BTW, while the signal has to be strong enough to be undistorted, position is determined from the information encoded in the signal, not signal strength.
OTOH, the determining factor between Magellan and Garmin may just be whichever model you can get the best deal on! Either way, ENJOY!
I really meant for this to be a quick reply.
Does it show that I'm an engineer?
Tom