CF GPS Receivers are great for both in-car usage for street routing applications, or for out of car use like for walking or hiking. Modern CF GPS Receivers also come with on-board memory for storage of map data.
These systems are usually compact, but do run on the power provided by your Pocket PC or Palm, so if you know that your average battery power for your PDA is say 5 hours, in most cases you will only see around 2-3 hours use with GPS Receiver. There are ways of getting around power problems by taking a battery extender with you on walks, and we have reviewed some in our GPS Accessories section of our reviews.