Types
In addition to the traditional handheld GPS, Garmin has the Foretrex series, which are wrist-mounted receivers perfect for when you need both hands available for a task.
Durability
Durability is important for those taking their Garmin GPS receiver into the woods or in the water. Even Garmin's most basic model, the eTrex, is waterproof rated at IPX7, making it able to withstand being in up to 1 meter of water for no more than 30 minutes. Another entry-level model is the Garmin 60, which has a toughened case and is also rated at IPX7.
Waypoints and Tracklog
Most Garmin GPS receivers are equipped with the ability to store up to 500 waypoints, which are coordinates that users can store for point of interest along the way. In addition, many Garmin models such as the eTrex come with a tracklog feature so you can keep a log of a path you have traveled with your GPS.
WAAS
Wide Area Augmentation System is enabled on all newer handheld Garmin models. WAAS increases the accuracy of the GPS to within 3 meters.
Battery Life
Many of the wrist-mounted devices take AAA batteries, which last between 15 to 18 hours. Other handhelds like the Garmin 60 take AA batteries, which last 28 hours, while some of the more advanced handhelds like the Oregon take both AA or lithium batteries.
