I purchased the BT-359 to use along with a Palm Tungsten E2 for use out in the woods for ecological research. I haven't yet taken it out in the field, but I have been successful in linking the two devices. Though, I'll admit that it took me a while. The problem came down to finding a freeware software program that would allow the Palm to operate with the GPS. I finally did come across Cetus GPS, which looks to be a great find! I only give the BT-359 4 stars because the user guide could be a bit clearer. I haven't yet decided if the size of the device will be a blessing or a curse! It would be great if they sold a fluorescent sleeve that fit the receiver.