I am by no means an expert on these. They have certainly come along way. I just heard about one (made by Garmin I think) called the Rhino. It is a combo GPS/Radio unit and when you talk to your partners via the radio it marks their location on the GPS. Handy safety feature should someone get lost or hurt in a block of woods you are not familiar with.

I use a Garmin Venture for both the woods and speed on my boat. They sell different moounts for different applications. Works great and at a good price.
Good Luck!