There are a lot of different types of manufactures and you will also want to think about doing the proper research. Course, you will find that it all depends on what you would like to do with the GPS system. You will find that there are GPS units that will help you to locate your position at any given time, but you will also find that there are many different GPS systems that do a lot of other thing as well.
When it comes to using the GPS tracking systems you will want to make sure that you are able to red this electrical maps. You will find that they can be a little static, but if you are able to read a map according to longitude and latitude, you will be just fine. You will want to keep in mind that when you go camping, you will need to make sure that the GPS unit battery life is very long. This is so that you dont end up getting lost in the wilderness and you will want to read up in the owners manual on how you can keep the length of the battery going strong so that you can be prepared for a good hike.
You may also want to get a waterproof unit, because you never know if you will run into some unexpected camping climate changes. Rain is not something that a lot...