I know that you have lots of brush piles committed to memory but that like everything else, too shall pass. With the gps up front you can mark stuff that you already know and find lots of other stuff to mark. It will really come in handy when you are hunting for those elusive specs. You'll be able to down load all of the mdc stuff that you have helped plant over the years.
For my own personal use down imaging is the best thing to come along in quite a while. You can actually see fish and tell which way they are looking.