Rick, lots and lots or options on a road worthy GPS. Can you define your intended GPS usage in a little more detail.
Such as, do you want it to talk to you? Maybe tell you what road name to turn on etc.
Would you like Blue Tooth or Phone connection options?
How about a large BRIGHT viewing screen?
Maybe riding-glove friendly.
I presume you want water proof or at least water resistant?
How about price? Are you looking at a certain price range?
A lot of us in the TCD use a GPS daily or at least weekly with a lot of diversity in choice, most seem quite happy with their personal choice.
Maybe show up at the TCD breakfast and Camping Demo next weekend as there will be a lot of riders sporting their personal choice in GPS devices. That way you can see, touchy-feely, and even play with the different GPS units to see what trips your trigger.