I use a Magellan eXplorist 710. After much careful consideration, I chose it over a Garmin 78sc. My primary reason for considering these two models is that they are both waterproof and submersible; very important features for kayaking.
I also use a Garmin 78 at
work, so I have considerable experience with both.
The Magellan may be at a slightly higher
price point, but it has features that the Garmin can't even touch such as inputting a new heading for a set distance (projecting a point) and then following the track directly to that point, among many others. The Magellan has digital
camera and video. At first it was more a gimmick than a consideration. In practice I use it much more than I ever thought I would and am grateful for the feature.
I also like that the Magellan is physically smaller with comparable sized
screen. Also the Garmin's buttons above the display just drives me nuts.
Magellan seems to have more cost effective map packages, but there seems to be fewer of them. It comes from the factory with a couple of killer map packages already installed. I also like Magellan's City series maps far more than Garmin's City Navigator maps. Most of Magellan's map packages are free, lifetime update able.
Garmin seems to have many more mapping options over all, including the ability to scan in your own maps but again, you pay for it. There is a site called Maps 4 Me that are nearly free downloads for Magellan for almost the entire world. Of course, you can always go with a
Navionics package, which I don't think the Garmin is able to use.
At home, Magellan's VantagePoint
software is about the easiest thing to use I have ever found and surprisingly powerful.
The downside? Magellan touch screen. Great idea but doesn't
work very well with wet sausage fingers or gloved hands. Buttons are better. The solution I have found is to use a low cost stylus like from a video
game or
iPhone. So far, Magellan's customer
service is kind of lacking. Their response time is very fast but their followup sucks.
For what I do, I would chose the Magellan again, hands down. I've had my unit for years and it has lived up to all my expectations. It is truly waterproof and submersible. It has never glitched or failed to operate in any way. It does everything I need it to do and I'm a pretty demanding user (surveyor by day, in my previous life)