Here are my work GPS units that I use every day. The Trimble is my primary and the Garmin 450T is backup. The Garmin is very accurate and battery life is great. The Trimble is able to download pretty much all file types. I primarily use the kmz and shape files. It is a map grade unit(not survey grade) but utilizes a program to apply differential coorection to make it pretty accurate...usually within 18-24".