My GPS 12 cost only slightly more than the ETrex units, and was a giant leap ahead in quality. After comparing reviews of the Garmin and Magellan units, I concluded that the GPS 12 would be the most reliable, and it really does seem to be. Once it aquires the available satellites, it really stays locked on--I've used it in the car on the passenger seat, on the armrest, in my lap, and it doesn't lose its position. I've even held it to a tiny airplane window and tracked my flight accurately. The biggest issue with lower-end GPS units seems to be their ability to hold a lock, and this one performs extremely well.