Reliability and durability depends upon the product that you buy. But , GPS is a proven technology that is effective. You get what you pay for. http://www.consumersearch.com/gps
The best price for a Garmin GPS is around $100-$200. They can be very inexpensive compared to other tracking machines and GPS and they are very durable and reliable.
Bodyglove manufactures a neoprene case for GPS handhelds.
Users complain that it is not durable. Also that it is also not a reliable gps system. You can find reviews on http://reviews.cnet.com/car-gps-navigation/lowrance-iway-500c/4505-3430_7-31411013.html
Yes, and you can also get the apps on your smartphones or ipod touches. I have used the ones for cars and phones, but not the ones that are handhelds.
You can find the difference between marine gps systems and garmin gps systems on the following site: http://www.secrets2business.com/the-difference-between-marine-gps-handhelds-and-their-bigger-brothers/. They have good descriptions.
Garmins outdoor gps units are made to be outside in the elements. And since they are made to be outside in the elements they are, in fact, very durable.
Handheld GPS systems are ideal for hikers and other outdoor enthusiasts. Handheld units are designed to be durable when subjected to rugged, harsh and vigerous conditions.
GPS systems tell it's customer where to go. Hopefully, this GPS system is reliable in it's ability to know exactly where it's customer is and where exactly it is going.
I think most gps systems are quite reliable if you learn how to use them properply. The tomtom use to be the most reliable one and then competinion came out and many are just as good.
You can find a second hand Extrex GPS at online stores such as Amazon or eBay. You can also find one on NexTag or ukrocketman. NexTag or Amazon are your best choices, because you will find a variety of different Extrex GPS handhelds at cheap prices.
A gps map is only as reliable as your access to Satelite signal. Camping in certain areas where the satelite signal is strong will allow you to be able to access gps map wherever you go.
According to users the Lowrance h2o gps is very durable. Many customers use this gps for hunting, fishing and other outdoor activities. One customer rating stated that they dropped it into the water and the gps survived. http://reviews.cabelas.com/8815/017032/lowrance-ifinder-h20-handheld-gps-reviews/reviews.htm?sort=submissionTime&dir=asc