Do you use an external antenna with the Navman? And how does it
track compared to the Garmin?


I had the Navman at first and was happy with it. Then I got a Bluetooth GPS
(Emtac although there are many others). The Bluetooth GPS is vastly
superior in time-to-first-fix as well as accuracy. There are a couple of
web sites that give reviews of GPS devices and compare them. Check out
http://www.gpspassion.com/en/hardware/gpslist.htm for a pretty complete
table. From that table, you can link to reviews for the different devices.